t4aleolm Alexander Ramsay

THESIS SUBMITTED I W PABTIAL FULPILLWENT OP

TRE REQUIREMENTS FOR THE D E G R E E OF

MASTER OF SCf EWCE

in the Department

o f

Biological Sciences

@ nalco la Alexander Ramsay 1980

Sf #ON FRASER UNIVERSITY

December 1980

All rights reserved, This work may n o t be r e p r o d u c e d i n whole or i n part, b y photocopy

or other Beans, without peraiss ioa of t h e author,

APPROVAL

Name : Malcolm A. Ramsay

. Degree: Master of Science

T i t l e of Thesis: Aspects of t h e reproduct ive biology of C a l i f o r n i a big-

horn sheep (Ovis canadensis c a l i f o r n i a n a ) on t h e

Ashnola p la t eau region of ~ r i t i s h Columbia

Examining Committee:

Cha irman : D r . R. W. Mathewes

D r . R. M. Sadlelr Senior Supervisor

-

D r . E. -B . Hartwick

Date approved 15 December 1980

PARTIAL COPYRIGHT LICENSE

1 hereby g r a n t t o Simon Fraser U n i v e r s i t y t h e r i g h t t o lend

my t h e s i s , p r o j e c t o r extended essay ( t h e t i t l e o f which i s shown below)

t o users o f t h e Simon Fraser U n i v e r s i t y L i b r a r y , and t o make p a r t i a l o r

s i n g l e cop ies o n l y for- such users o r i n response t o a reques t f rom t h e

l i b r a r y o f any o t h e r u n i v e r s i t y , o r o t h e r educa t iona l i n s t i t u t i o n , on

i t s own beha l f o r f o r one o f i t s users. I f u r t h e r agree t h a t permiss ion

f o r m u l t i p l e copy ing o f t h i s work f o r s c h o l a r l y purposes may be g ran ted

by me or t h e Dean o f Graduate S tud ies . I t i s understood t h a t copy ing

o r p u b l i c a t i o n o f t h i s work f o r f i n a n c i a l g a i n s h a l l n o t be a l lowed

w i t h o u t my w r i t t e n permiss ion.

T i t l e o f Thes i s /Pro ject /Extended Essay

Aspects of t h e reproduct ive biology of Ca l i fo rn i a bighorn sheep

(Ovis canadensis e a l i f o r n i a n a ) on t h e Ashnola p l a t eau reg ion of

B r i t i s h Columbia

Author:

( s i g n a t u r e )

Malcolm A. Ramsay

(name)

ABSTRACT

O c c a s i o n a l c o u n t s o f t o t a l numbers of b i q h o r n s h e e p i n t h e

Ashnola p l a t e a u r e q i o n of B r i t i s h C ~ l u m b i a i n ?.he years

p r e c e d i n q 1976 i n d i c a t e d a low d e n s i t y and a n a p p a r e n t l y

d e c l i n i n g ~ o p u l a t i o n , T h i s p a t t e r n was c o n f i r m i l b y requlas

c o u n t s c o n d u c t e d i n t h i s study from 1976 t o 1380, T h e d e c l i n e

a p p e a r s t o b e due ta a very low r e c r u i t ~ e a t of lambs i n t o t h e

p o p u l a t i o n , T h e s t u d y i n v e s t i q a t e d the c a u s e s of t h i s level o f

r e c r u i t m e a t and d o c u a e n t s t h e effects of a l t e r i n q one of t h e

v a r i a b l e s which Bay b e c a u s a l ,

The ro le of t h e f o l l o w i n g factors upon t h e b i o l o g y of the

Ashnola b i q h s r n p o p u l a t i o n were s t u d i e d : su@mer sanqe burninq i n

r e l a t i o n t c r a l t e r i n q s u m e r n u t r i t i o n ; w i n t e r s u p p l e m e n t a l feed

proqrantl i n r e l a t i o n t o a l t e r i n g w i n t e r n u t r i t i o n ; chanqes i n

w i n t e r c l i n a t i c s e v e r i t y ; p o s s i b l e effects of p r e d a t o r s a t t h e

tirae of lamb d r o p a n d t h e ro le of p a r a s i t e loads, I t was

c o a c l a d e d t h a t t h e a a i n cause of the low r e c r u i t r a e n t rates was

the low l e v e l o f w i n t e r n u t r i t i o n a v a i l a b l e t o t h e b iqhorn

sheep. S u p p Z e a e n t a l feed proqraas o v e r t h r e e w i n t e r s were

f o l l o w e d by c o n s i d e r a b l y i n c r e a s e d l a ~ b / e , w e r a t i o s .

#anaqement r e c o a l ~ e n d a t i o n s r e s u l t i n q f ro& t h e s e c o n c l u s i o n s

are o u t l i n e d ,

Research among t h e ranges a f f o r d s t h e p u r e s t p leasure

I know, one which goes beyond t h e c o l l e c t i n g of f a c t s

t o one t h a t becomes a ques t t o appra i se our va lues and

look f o r our p lace i n e t e r n i t y . When a t dusk t h e

r a d i a n t peaks a r e deprived of t h e s u n ' s f i r e , leaving

them gloomy and deso la te wi th cold prowling t h e i r s lopes ,

one f e e l s imprisoned by rock, bu t when l a t e r , white i n

t h e moon, t h e g l a c i e r s glow l i k e v e i l s of f rozen l i g h t

a l l d i f f i c u l t i e s vanish i n t h e presence of such

pr imordia l beauty.

- G.B. Scha l l e r (1977)

I t h a n k Dr. R . # , F , S , S a d Z e i r for h i s consistent

e n c o u s a q e n e n t , a a v i c e a n d c o n s k r u c t i v e cri t icis@ t h r o u q h o u t t h i s

s t u d y and e s p e c i a l l y during i t s darker moments, Thanks are a f s o

d u e D r , 8 . H a r t w i c k o f irty s u p e r v i s o r y c o n m i t t e e ,

1 afso t h a n k the f o l l o w i n q p e r s o n s i n v o l v e d i n t h e

g o - o p e r a t i v e Okanaqan B i q h o r n S h e e p R e s e a r c h G r o u p for

a s s i s t a n c e i n s a n y Prays: J, Bone, D. Eas tman , D. Hebert and 1.

g o b e r t s c t n of the British Colulafiiia F i s h a n d H i l a l i f e Branch; Ed,

Harold a n d Ronard Laeey of t h e Okanaqan G a m e Earn; a n d A ,

B o t t r e l l , R e Eccles, W , P e t e r s o n , He P i t t , D. S h a c k l e t o n a n d B,

Wikeem of the U n i v e r s i t y of ~ r i t i s h CoPuiabia,

The n e m b e r s of the K e r e ~ e o s - C a w s t a n S p o r t s ~ e n ~ s Association

&ere most h e l p f u l and s u p p l i e d me w i t h cr i t ical i n f o r m a t i o n ,

T h a n k s are e s p e c i a l l y due to K, 6 R e Andrews, A, Boittrell,

fI. Cleator, R* Eccles, K, Gardner, Em Lemon, D. F 8 , Loomer, f.

fiessier, E, P e i t s o , G, R o b i t a i l l e , D, Seip, G. Se i i th , a n d EI, E

R, Pyborn f o r @ugh a p p r e c i a t e d a s s i s t a n c e i n t h e f i e l d ,

I would l i k e to t h a n k D. Emsley of U , B , C , for a s s i s t a n c e

with faecal a n a l y s i s and for qeaeral a d v i c e a b o u t n e n a t o d e

b i o l o g y ,

1 owe e s p e c i a l t h a n k s t o E, Peitso for a d v i c e a n d

a s s i s t a n c e i n a r r a n q i n g the f i n a l d r a f t of the n m a u s c f i p t ,

C o n v e r s a t i o n s u i t h 8, Cleator, F, Hessier a n d D, Seip Mere

a l w a y s s t i rnu la t inu ,

PI, and R, H e l l i s h a l l o w e d me the peace to coaple te much of

a y work and for this and a l l else X thank them,

20 r ~ y parents, A, and I, Ratway, 1 a@ f o r e v e r qrateful for

their c o n s i d e r a b l e support and encouraqeaent all these years,

Financial suppor t was provided b y t h e B r i t i s h Columbia F i s h

and g i l d l i f e Branch a n d Sinon Fraser University.

TbBLE OF CONTENTS . . A ~ p f 0 ~ a 1 . . . . ~ . ~ ~ . . . . ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ . ~ ~ ~ . ~ ~ ~ ~ ~ ~ ~ ~ . . . ~ ~ . ~ ~ . ~ . ~ ~ ~ . . ~ ~ ~ ~

Q u o t a t i o n .................................................... iv

Bcknowledqments ...............................................~ * * . L i s t of T a b l e s o ~ ~ e e . e ~ . 8 ~ e e e . ~ ~ e e 1 e e e ~ ~ a ~ ~ e e ~ e ~ ~ e ~ 1 . ~ e e ~ e ~ ~ *VXIX

List of f i q u r e s .............................................. ix

I. General f n t r o d u c t i o n a............................e.... 3

XI. F a c t o r s P o t e n t i a l l y A f fec t i n q R e p r o d u c t i v e Success in Biqhorn Sheep ...........a,............b.......... 1 4

PIX, Methods e . e e e m . e 8 . e e s e e a e e , . . e e * e e e ~ * s e o e ~ * e e o e e e e e e 2 9

Capture proqram .....................e....e.......... 29

IV. R e s u l t s ..............................I.........e.... 39

Capture proqsaa m................................. . * . 3 9

P o p u l a t i o n Changes .................................. 45

Use of Slopes R e l a t i v e t o Burns ................... ,,57

Supplementa l Uinter Feed PrograB ................... .58 ................................. Effects of C l i n m t e . 6 1

...... Predat ion e e e ~ e ~ e ~ e e ~ e e ~ e ~ e e ~ ~ e s e L ~ ~ ~ ~ e e e i C e ~ e ~ ~ 6 7

P a r a s i t e s ........................e................. .69 Y e D i s c a s s i o n and C o n c l u s i o n s ........................... 75

APPENDIX I e r e e r r ~ o * * m r ~ e * e e ~ ~ ~ a e e * e o ~ ~ e s e * e e * e e e e e e e e e e ~ a e ~ e ~ 8 ~

APPEMDfX If e e e m o e e e e e * e * * e e m e , e * e * e * * e * e * * e o a o e e e e e e e o e e * e e s * 8 4

LITERATURE CITED e . e . , e e o e e o , e * e * e e e * e e e o e e o s a e * e r . o . a e o s a o * o * e 9 Q

v i i

LIST OF TABLES

Table 1

Table 2

Table 3

Table 4

Table 5

Tahle 6

Tahle 7

Page

Daily counts of sheep numbers from the Ashnola study site for the years 1978 - 1980............ 46

California bighorn sheep spring census data ....... from the Ashnola study site (1970 - 1980) 53

Lamb survival to age one year old (1971 - l98O)... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Determination of amount of additional protein available to ewes in winters of supplemental feeding ......................................... 62

Long term (19i1 - 1970) means for daily temperature ( C) and total precipitation (mm) taken at Keremeos..,,.........,......,.......... 64

Winter severity index calculated from differences between 30 year norm meteorological data from Keremeos for MEAN DAILY TEMPERATURE and TOTAL MONTHLY PRECIPITATION and monthly data for the study years (1970 - 1980)..... .................. 65

Incidence of lungworm (Protostrongylus sp.) infection in Ashnola bighorn sheep herd......... 70

viii

LIST OF FIGURES

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Map of B r i t i s h Columbia showing the research s i t e . .............................. Estimates of popula t ion s i z e of t h e herd of C a l i f o r n i a bighorn sheep winter ing on ranges e a s t of t h e ~ s h n o l a River i n southern B r i t i s h Columbia f o r t h e years 1959 - 1969..

Aer ia l view of s tudy a r e a showing t h e open grass land s lopes used by t h e bighorn sheep i n winter . . . . . . . . . . . . ....................... Schematic flow c h a r t i l l u s t r a t i n g reproductive opt ions a v a i l a b l e t o a bighorn ewe during a s i n g l e annual cyc le ......................... Aer ia l photograph of s tudy s i t e showing t h e census zones de l imi ted by t h e B r i t i s h Columbia F i sh and Wi ld l i f e Branch. . . . , . . . . . .

Aer ia l view of s tudy s i t e showing t h e census rou te walked..... ........................... B e s t e s t ima tes f o r populat ion s i z e , wi th 95% confidence i n t e r v a l s , f o r t h e study herd (1970 - 1980). ..............................

Page

3

Lamb:ewe r a t i o s f o r t h e years 1970 - 1980. , , 59

Rela t ionship between times of supplemental win te r feeding i n 1977 - 1980 and t h e approximate s t age of g e s t a t i o n f o r t h e F l a t i r o n herd. To ta l amount of suppl.ementa1 feed placed ou t i s shown f o r each y e a r . . . . . , 6 3

Figure 10 Rela t ionship between 1arnb:ewe r a t i o of each yea r and t h e previous w i n t e r ' s s e v e r i t y index f o r t h e years 1970 - 1980 ............. 6 6

1. General Int xoduc ti on

S e v e r a l r e s e a r c h e r s have e x p r e s s e d c o n c e r n regardinq tbe

s u r v i v a l cf b i q h o r n s h e e p [Ov i s m a d e n s i s Shaw) t h r o u q h o u t

North Aaerica f 0 u e c h a e r $350, S p a l d i n q E M i t c h e l l 1370, S t e l f o x

1971) . S u c h concern has ~ l a n i f e s t e d i t s e l f i n B r i t i s h Columbia b y

t h e i n i t i a t i o n o f s e v e r a l s t u d i e s h t o t h e r anqe re la t ions and

g e n e r a l Bio loqg of b i q h o r n sheep . Bore e f f o r t h a s been p u t into

s t u d y i n q h i q h o s n s h e e p i n B r i t i s h Columbia t h a n would b e

expecked f r o g a sirtrple c o n s i d e r a t i o n of their numbers (Anon.

1978b, B u n n e l l 32 g%. 1978),

The British Columbia F i s h and g i l d l i f e Branch h a s a mandate

t o c o n s e r v e and, where a p p r o p r i a t e , i n c r e a s e t h e size of

t e r r e s t r i a l vertebrate p o p u l a t i o n s i n t h e p r o v i n c e fAnon.

1378a). Many of t h e d e c i s i o n s of t h e b ranch must be lnade with

r a t h e r i ncog lp l e t e hnowledqe of t h e colrtplex i n t e r r e l a t i o n s h i p s

between the a n i a a l s aanaqed a n d t h e i r e n v i r o n m e n t , T h i s

s i t u a t i o n a r i s e s d u e t o t h e l i ~ i t e d f u n d i n g a v a i l a b l e for

r e s e a r c h i n t o the e c o l o g y of t h e s p e c i e s unde r ~anaqar ia f

c o n s i d e r a t b a , Consequen t1 y c u r r e n t r e s e a r c h i s p r i m a r i l y

d i r e c t e d toward t h o s e s p e c i e s which are c o n s i d e r e d e i t h e r i n t h e

q r e a t e s t d a n q e s of e x t i r p a t i o n , or of s e v e r e p o p u l a t i o n decline

o r where t h e r e i s c o n s i d e r a b l e p u b l i c i n t e r e s t i n a s p e c i e s

(Eastnta~ 1979) s

Buch of t h e r e s e a r c h on b i q h o r n s h e e p in British Columbia

h a s i n v o l v e d the population f o u n d i n t h e Ashnola River w a t e r s h e d

of s o u t h - c e n t r a l 3. C. ( P i q u r e 1). The b i o q e o c l i m a t i c zone and

g e n e r a l f e a t u r e s o f t h e Ashnola r e g i o n are d e s c r i b e d b y Eluod

( 1 963a) and Schef fles (1 373) . Al thouqh the Ashno la biqhorn sheep h e r d is o n e of the

l a r q e s t p o p u l a t i o n s of California b i q h o r n sheep (& 2,

c a l i f o r n i a n a ) e x t a n t { S p a l d i n g & H i t c h e l l 1370). it is t h o u q h t

t o h a v e d e c l i n e d a p p r e c i a b l y in size since t h e l a s t century, X t

h a s b e e n suqgested t h a t t h i s d e c l i n e h a s been due t o human

a c t i v i t i e s and a l i e n a t i o n of h i s t o r i c sheep r a n q e (Biood 196 I ,

S c h e f f l e r 1 9 7 3 ) , Durinq t h e 19508s and 3959's t h e he rd appeared

to be s table i n s i z e { F i g u r e 2 ) w i t h relatively h i q h l a a b i n q

rates 050 l a a b s / t 0 0 e n e s ) b u t r e l a t i v e ly poor juvenile sur viva1

(Blood 3961, Dentarchi 11365) . Research for five master's t h e s e s , u n d e r q r a d u a t e p a F e r s and

several s t u d i e s by the British Colulrtbia F i s h E; Wildlife Branch

have B e e n c o n d u c t e d upon the Ashnola sheep h e r d a n d its r a n q e

{Blood 5361, Bone 1969, D e ~ a r c h i 1965, Harpe r 1963, Mayaard

1972, Wosrison 1972, Ramsay 3976a, Scbeffler 1373, Spa ld inq

1971, 1973) . D e s p i t e t h e d e q r e e of e f f o r t which h a s b e e n p u t

i n t o t h e s e s t u d i e s t h e d y n a a i c s of t h i s p l a n k : h e r b i v o r e system

are still not well understood,

FIGURE 1 Map of British Columbia showing the research site,

FIGURE 2 Estimates of population size of the herd of California bighorn

sheep wintering on ranges east of the Ashnola River in southern

British Columbia for the years 1959 - 1969. Estimates from

Blood 1961, Demarchi 1965, Scheffler 1973, Sugden 1961, and

British Columbia Fish and Wildlife Branch unpublished data.

TOTAL NUMBER OF SHEEP

The A s h n o l a biqhorn sheep p o p u l a t i o n is d i v i d e d i n t o 2

d i s c r e t e bands with l i t t le m v e m e n t b e t ween them [Blood 1953a) . The p r e s e n t study i s c o n c e r n e d w i t h t h e band l y i n q east and

south of t h e A s h n o l a R i v e r a n d a i n t e r i n q on F l a t i r o n M o u n t a i n ,

T h i s band r a n g e s over a n area o f a p p r o x i ~ t l a t e l y 500+ sq, km, i n

summer, b u t i n w i n t e r is r e s t r i c t e d t o d i s c r e t e r a n q e s on

s o u t h - f a c i n g s l o p e s t o t a l l i n q a p p r o x i m a t e l y 550 h a , ( S p a l d i n q

1971) , T h e s e s l o p e s are shorn i n F i q u r e 3, O f t h e s e w i n t e r

r a n q e s t h e mos t i a p o r t a n t is known as S o u t h Slope which covers

a p p r o x i a a t e l y 280 h a , fRaeasay 1976a, S p a l d i n q 197 3 ) . S o u t h S l o p e

r e c e i v e s the h e a v i e s t use b y the band between November a n d June,

a n d e a p e c i a f l y by t h e f e ~ a l e a n d j u v e n i l e conzponent of the band

d u r i n g t h e l a t t e r p o r t i o n o f t h i s p e r i o d ,

Ewes q i v e birth ta l a m b s on t h e s o u t h a n d vest facinq

c l i f f s found on t h e west s i d e of S o u t h S l o p e , T h e y utilize t h e

q r a s s y s l o p e s adjacent t o t h e l a m b i n q c l i f f s for q s a z i n q for

s e v e r a l d a y s a f t e r p a r t u r i t i o n ,

S t u d i e s by B l o a d f 1961) and Dezsarchi (19653 demonstrates

that k e y winterinq g r a s s l a n d r a n g e s of t h e b i q h o r n sheep were i n

a r e t r o q r e s s e d and r a t h e r p o o r c o n d i t i o n . It was s u q q e s t e d t h a t

i r a p r o p e r a a n a g e l a e n t of d o a e s t i c l i v e s t o c k , which had b e e n qrazed

on t h e r a n q e s since t h e l a t e 19th c e n t u r y , h a d r e s u l t e d i n t h e i r

o v e r q r a r t e d condit%on, S c h e f f l e r (1973) s u q q e s Z e d t h a t t h e

q e n e r a l l y p o o r p r o d u c t i v i t y of t h e B s h n o l a basin s o i l s d i c t a t e d

a q a i n s t a n y deqree of i n t e n s i v e l i v e s t o c k qraziaq,

FIGURE 3 Aer ia l view of s tudy a r e a showing t h e open grass land s lopes

used by t h e bighorn sheep i n winter . North i s t o t h e t o p of

t h e page,

Blood t1961) was u n a b l e t o f i n d evidence of direct

c o a t p e t i t i o n between d o m e s t i c l i v e s t o c k and biqborn s h e e p on the

maf o r s h e e p w i n t e r i n q r a n q e s , I n 1%8, w h i l e S c h e f f l e r 1 197 3)

was c o n d u c t i n q s t u d i e s t o d e t e r s i n e the deqree of competition

bet s e e n w i l d a n d domes-l ic u n g u l a t e s , t h e B,C. F i s h and g i l d l i f e

Branch purchased the g r a z i n g r i q h t s f o r %he Ashnofa sheep ranqes

a n d r e ~ o v e d a l l d o ~ e s t i c l i v e s t o c k . T h i s r e s u l t e d i n an increase

in foraqe p r o d u c t i o n , a c h a n g e i n species c o n p o s i t i o n and a

q e n e r a l ia tproventent in t h e o v e r a l f . r a n q e c o n d i t i o n v i t h i o one

a n d a h a l f gears of cattle r e s o v a f ( S c h e P f P e r 1973). The

arqut t lent j u s t i f y i n q the p n r c h a s e of the q r a z i n q s i q b t s was that

t h e l o n g term suartler q r a z i n q of dopaestic: l i v e s t o c k o n t h e s h e e p

w i n t e r r a n g e s had r e s u l t e d i n a r e d u c e d carryinq capacity of

these ranqes far B i g h o r n sheep, It was felt t h a t t h e sheep

p o p u l a t i o n would r a p i d l y r e s p o n d t o the i s p r o v i n q r a n q e s with

increased l a m b and a d u l t s u r v i v a l . A three-pear s t u d y was bequn

i n 1969 t o document a n y c f ianqes i n herd s t r u c t u r e and dynamics

which r i q h t r e s u l t frea t h e catt le remova l . The e x p e c t e d rise i n

nuethers was not r e a l i z e d (Raesay 1976a, S p a l d i n q 197 1) . Wok o n l y

d i d t h e h e r 4 n o t i n c r e a s e i n s i z e after ca t t le removal but there

was some e v i d e n c e k h a t il riqh.1: actually be slowly d e c l i n i a q

(Ramsay 197i5af . A d d i t i o n a l l y t h e Iaetbzewe r a t i o a p p e a r e d 4,0 h a v e

Beefined s i n c e the e a r l y 1950*s f B , Webster, unpublished field

n o t e s ) ,

T h i s d i s c o u r a q i n q r e s u l t l e d t o a new series of m a n a q e r i a l

m a n i p u l a t i o n s , b e q i n n i n q i n t h e early 1970 % a n d c o n t i n u i a q

throuqh the presenk s t u d p ,

1. 1973: A coyote (c_an&,s L a t r a n s ) removal, program u s i n q poison

bait was c a r r i e d out f o l l o u i n q a s i n i l a r proqram i n t h e

early 3950 's /Blood 1961, S p a l d i n g 1973). Weither of these

p r o q r a ~ s was m o n i t o r e d well enough t o a c c u r a t e l y determine

t h e i r e f f e c t i v e n e s s . However no evidence of increased lamb

s u r v i v a l as d e c r e a s e d ~ o r t a l i t y was observed a f t e r t h e 1973

c o n t r o l p r o q r a a [B,C, Fish and gildlife, u n p u b l i s h e d data) ,

Cooqar ( F e l i s ~ - 9 ~ ) were hunted and coyote were a c t i v e l y

t r apped i n t h e Ashaola w a t e s s h e d t h r o u g h o u t t h e 1950's

{Blood 1 95 1)

2, 1974 - present: L i m i t e d entry rarit huntirtq r e p l a c e d the open

ralri s e a s o n which had been i n effect s i n c e 1P5&, Compulsory

reporting of k i l l s was introduced i n 1975 and has c o n t i n u e d

to t h e p r e s e n t , an a v e r a q e of 7.33 r a a s / g e a r were r e m v e d

from the F l a t i r o n he rd p r io r : to the Xiraited entry h u n t 13970

- 1972) and 3.67 ran ts /year af ter t h e inception of Lira i t ed

entry huatinq f f g J 4 - 1979) IB,C, F i s h E Wildlife,

unpubf i s h e d d a t a ) ,

3, I976 - present: A controllea burning proqrae was bequn on

the w i n t e r r a n q e on South S l o p e i n t h e sprinq of 1975 a n d

. r a n q e b u r n i n g h a s o c c u r r e d each s p r i n q since,

4. 3977 - presen t : fn t h e % i n t e r of 1977/78 a s u p p l e ~ e n t a l

w i n t e r f e e d i n q proqram c o n s i s t i n q of commercial sheep

p e l l e t s , a ineral m i x and a n t i - h e l ~ i n t h i c drug was bequn,

The earlier studies c a r r i e d out i n t h e Ashnala w a t e r s h e d

tended to focus upon t h e range conditions and the impact of the

v a r i o u s h e r b i v o r e s upon t h e f l o r i s t i c c o m ~ u n i t y r a t h e r t h a n upon

t h e s h e e p themse fves . Horsever ~ a n a q e r i a l d e c i s i o n s a b o u t a

s p e c i f i c population r e q u i r e i n fo r lnaL lon about the factors which

li~it t h a t p o p u l a t i o n ,

Al. t h o u g h Blood (1 96 1) and Demarchi ( f%5) a d d r e s s e d so ae

aspects of the d y a a n i c s of the Ashnola sheep p o p u l a t i o n , t h e s e

were not zmjor Shelnes of t h e i r s t u d i e s , Natality and mortality

u i t h i a the herd was p o o r l y u n d e r s t s o d , Blood ( 1 % 11 and Bone

{ t969 ) c a l c a l a t e d Life history t ab les from a small. c o l l e c t i o n of

skulls collected fro^ t h e sheep ranqes over a p e r i o d of Bang

Tears, B l t h o n g h h i s d a t a base was srilall, Blood 41967 1 concluded

that h i q h p o s t - n a t a l and a d u l t m o r t a l i t y was checkinq potential

population q r o u t h , The causality and i m p a c t of t h e r e l a t i v e l y

low l ambinq snccess i n the 1930's has not been i n v e s t i q a t e d ,

Given t h e s t a t e - o f - t h e - a r t o f w i l d l i f e manaqement i n the

Ashnofa watershed i n the @id-1970", i t was c o n s i d e r e d

reasonable t o direct a t t e n t i o n directly t o the sheep the tase lves

to see i f t h e proximal. c a u s e s of a o r t a l i t ' y a n d / o r Tow natality

rates c o u l d be d e t e r a i n e d , Pf t h i s c o u l d be done wi th som

d e q r e e of r e f i n e m e n t %hen r e l a t i v e l y random tactics could be

replaced w i t h sore precise a a n a q e r i a l . d e c i s i o n s which s h o u l d ,

p o t e n t i a l l p , be mre c ~ s t ef f e c t i a e and saccessfuf ,

Xt was t h e oriqinal intent of this s t u d y t o d e t e r s i n e the

causes of the f e f a t i v e l y low spring laaxb:ewe r a t i o s observed i n

t h e Flatiron h e r d , Lou o b s e r v e d l a a b i n q sates c o u l d b e d u e t o a

number of f a c t o r s :

1, Ion a n n u a l c o n c e p t i o n rate,

2. sotite p r o p o r t i o n of ewes breed o n l y e v e r y 2nd year,

3. a hiqh rate of s p o n t a n e o a s a b o r t i o n o r r e s o r p t i o n .

4, a hJgh rate of pos t -na ta l , m o r t a l i t y d u e t o e i t h e r p r e d a t i o n ,

clisatic stress, disease, or ewe a b a n d o n ~ e n t of lambs,

The 1amb:ewe ratios r e p r e s e n t c o u n t s made i n spring d u r i n q

the latitbinq season , However bighorn ewes in the Ashnola reaain

in s e c l u s i o n o n the laabinq cliffs for s e v e r a l d a y s after

p a r t u r i t i o n , Consequen t 2 y fasbs are n o t seen i m a e d i a t l y upon

birth (Blood 3 9 6 f ) . C e i s t (19711 suqqested that %his was t h e

qeneral pattern o f naouratain sheep, a o v i n q o n t o lambing areas

prior t o p a r t u r i t i o n and s e a a i n i n q i n s e c l u s i o n fo r some 5 - 10

days , Berqer (1978af houeve r refers t o observations made of a 1

- 2 day old laab in s o u t h e r n C a l i f o r n i a ,

I n the Bshnola s t u d y s i t e t h e sheep a p p e a r t o f o l f o e the

pattern d e s c r i b e d by G e i s t (1971) and t h u s 1arab:eve ratios have

been d e r i v e d f ram c o u n t s made s e v e r a l d a y s after t h e first lambs

a r e born a a d a t v a r i o u s t i a e s t h r o v q h o u t the s u b s e q u e n t l a ~ b i n q

period,

H i s t o r i c a l l y s t u d i e s of r e p r o d u c t i o n i n free-ranqinq

u n q u l a t e s h a v e r e q u i r e d larqe k i l l s a a p l e s from the p o p u f a t i o n

&q. f Hasake 1977, S i a p k i n 19?4) , T h i s is c l ea r ly an

i n a p p r o p r i a t s technique f o r u s e o n a small, isolated population

of b i q h o r n s h e e p where p u b l i c and p r o f e s s i o n a l c o n c e r n is felt

fo r t h e i r c o n t i n u e d e x i s t a n c e ,

Ra~say a n d Sadle ir (1979) d e v e l o p e d a s i ~ p l e pregnancy test

f o r b i q h o r n sheep c o n s i s t i n q af a sinqle blood assay for

p r o q e s t e r o n e titre from s a ~ p l e s taken from e v e s d u r i n q the

latter h a 1 f of * s t a t i o n (lkppsndix If). T h e method is reliable

and n o n - d e s t r u c t i v e , b u t requires a b l o o d sample fro@

f r e e - r a n q i n q ewes i f the test is to be used in the field, A t the

outset of this study i t was hoped t o u s e this technique t o

detect e a r l y preqnancy i n t h e ewes without r e y u i r i n q t h e t i l l i n q

&embers of t h e p o p u l a t i o n ,

!iy original research p l a n uas to:

Census the P l a t i r o n herd r e g u l a r l y over a 2 - 3 year period t o d e t e r m i n e t h e total number of sheep p r e s e n t and t h e

1aab:ewe rat ios for t h o s e y e a r s ,

D e t e r m i n e the time w i t h i n t h e r e p r o d u c t i v e s e q u e n c e r h e n

r e c r u i t ~ e n t i s reduced by;

a. c a p t u r i n q a n n a b e r of ewes before t h e time of

p a r t u r i t i o n a n d usinq bhood assays to determine I f t h e

females were p r e g n a n t and b y ;

be i n d i v i d u a l l y t a q q i n q a n d c o l l a r i n g t h e same a n i a a l s and

o b s e r v i n q t h e a d u r i n q and after t h e larxlbinq period to

d e t e z m i n e t h e d e g r e e of i a a e d i a t e p o s 2 - n a t a l m o r t a l i t y

of t h e i r l a ~ b s , The preqnancy s t a t u s of t h e ewes salnpfed

would qive soae i n d i c a t i o n of t h e p reqnancy f a t e w i t h i n

the h e r d .

3. I hoped t o q a i n a d d i t i o n a l . i n f o r m a t i o n on;

a, the effectiveness o f t h e c o a t m u l t p r eqnancy

d e t e r a i n a t i o n method,

b, t h e degree of b i - a n n u a l b r e e d i n g o f t a q q e d ewes t h f o u q h

o b s e r v a t i o n s a a d e d u r i n q s u b s e q u e n t ruts and breedinq

per iods .

c, the utaveatents o f an iaa l s betoeen p o p u l a t i o n s b y

s i q h t i n g s of taqqed aniraals,

d . an i n d e p e n d e n t test of h e r d size using a i a o d i f i e d mark - r e c a p t u r e aethod,

e, levels of l u n q u o r a burden d u r i n g spriaq and summer,

f, i n c i d e n c e of p r e a a t o s s w i t h i n t h e s t u d y area d u r i n q the

laabinq p e r i o d ,

The B , C , Pish and g i l d l i f e Branch c a r r i e d o u t s e v e r a l

nanaqesial m a n i p u l a t i o n s d u r i n q the c o u r s e of t h i s s t u d y . T h e s e

i n c l u d e d s u p p l yinq v i n t e r feed s u p p l e a e n t s , t r e a t i n g t h e h e r d

w i t h t h e a n t i - h e l m i n t h i c d r u q T h i a b e n d i z o l e , and b u r n i n q parts

of t h e w i n t e r r a n g e s i n t h e s p r i n q . f was ab le t o p a r t i a l l y

s a q i p u l a t e the w i n t e r feed and a n t i - h e l m i n t h i c d r u q proqrarxls i n

a n effort t o determine what e f f e c t s winter f o t a q e a v a i l a b i l i t y

and parasite loads miqht have upon reproductive performance

within t h e herd,

11, Factors P o t e m Z i a l P y if fectinq f e p r o d u c t i v e Success in

Bighorn Sheep

N u t r i t i o n , disease, p a r a s i t e s , p r e d a t o r s a n d qeneral stress

factors can a l l potentially affect the r e p r o d u c t i o n process from

conception t o p a r t u r i t i o n a n d n e o n a t e s u r v i v a l f rum birth t o

weaning (Eloen 1973, R a t t r a y 1977, S a d l e i r 196'3, Speddinq 197C) . However the a c t u a l i n f l u e n c e , e i t h e r a l o n e or i n concert, of any

o n e of t h e s e aqents upon a p a r t i c u l a r p o p u l a t i o n c a n be q u i t e

v a r i a b l e ( # o m 1973, Post 1975).

Because o f t h e e x t r e m e l y c o a p l e x relaZionship between these

eroqenous f a c t o r s a n d t h e r e p r o d u c t i v e performance of a

p a r t i c u l a r u n q u l a t e p o p u l a t i o n , simple m a n a q e r i a l s o l u t i c n s run

t h e r i s k of f a i l i n q to meet t h e i r c lb - j ec t i ve s (Bunnell &. 1978). B a s i c s t u d i e s s h o u l d be carried o u t t o d e t e r m i n e just

which f a c t o r s are X i m i t i n q a p o p u l a t i o n b e f o r e manaqerial

m a n i p u l a t i o n s are e f f e c t e d ,

A brief r e v i e w of some of these factors i s i n o r d e r .

More is known of t h e effects of n u t r i t i o n upon reproduction

in 'urtqulates than of the effects uf t h e o t h e r f a c t o r s l i s t e d

above, T h i s is e s p e c i a l l y true of d o m e s t i c livestock (Hafez E

Dyer 1959, R a t t r a y 1979, Speddinq 1970),

F i g u r e 4 s c h e m a t i c a l l y shows t h e p o t e n t i a l effects of the

n u t r i t i o n a l status of t h e f e s a i e upon h e r r e p r o d u c t i v e s u c c e s s .

Tbe flow c h a r t r e p r e s e n t s o n e complete reproductive cycle f o r a

b i q h o r n ewe, Bach aiamond r e p r e s e n t s a d e c i s i o n point for the

f e m a l e b a s e d upon h e r p h y s i c a l c o n d i t i o n . U n f o r t u n a t e l y these

key condition p a i n t s are n o t sole1 y d e p e n d e n t upon t h e ewers

n u t r i t i o n a l h i s t o r y to t h a t point i n time, O t h e r factors such a s

weather , parasite l o a d , d i s e a s e and stress a l s o c o n t r i b u t e t o

the ewe8s overall, p h y s i c a l c o n d i t i o n fSadlLeir 1969) . Althouqh

each o f these o t h e r factors n i l 1 b e c o n s i d e r e d s e p a r a t e l y , t h e i r

s y n e r q i s t i c effect a u s t be rentembered,

The b i g h o r n s h e e p i s a seasonal b r e e d e r in the n o r t h e r n

portio:: of its sirnqe with a discrete a u t u t n n r u t ( G e i s t 197'3,

Suqden f 951) . A f e m a l e e n t e r i n g the r u t c a n e i t h e r o v u l a t e o r

n o t o v u l a t e , A n o n - o v u l a t i n g f eaale f o r e q o e s any r e p r o d u c t i v e

a c t i v i t y until t h e followinq year,

T h e r e are 2 ga in c a t a q o r i e s of aniaals t o consider a t this

d e c i s i o n tree, that of a younq n u l l i p a r o u s f e a a l e and t h a t of an

o l d e r p o s t - p u b e r a l female. A younq f e m l e is Bore l i k e l y t o be

a f f e c t e d by a n a d v e r s e n u t r i t i o n a l plane t h a n would he a n o l d e r

f e ~ a l e due t o her s a a l h e r body size a n d c o r r e s p o n d i n s f p lesser

r e s e r v e s , S h e would b e less b u f f e r e d a g a i n s t e n v i r o n ~ e a t a l

s Z r e s s t h a n wanld older, h e a v i e r fetsales (Verme 1 9741,

FIGURE 4 Schematic flow chart illustrating reproductive options available

to a bighorn ewe during a single annual cycle. Diamond figures

are decision points based upon the ewe's physical condition at

that point in time. The model is described more fully in text.

NO

T O

VU

LATE

3 O

VU

LATE

SIN

GLE

M

ULTIP

LE

OV

ULA

TION

O

VU

LATIO

N

-

AB

OR

T 6

1 Condition of

Q

affects birth w

eight w

hich I I strongly affects

the probability

of neonate I

survival

I

4

3

I

LAC

TATIO

N

FAILU

RE

3 LA

CTA

TION

Sexual m a t u r a t i o n i n n o r t h e r n b i q h o r n f e n a l e s occurs a t

a p p r o n i a a t e l y 2 ,5 y e a r s ( G e i s t 197 1, S-treeter 1971)). I n

c a p t i v i t y fesales may reach puberty a t 1.5 y e a r s [J, B e r q e r ,

pers. comm.) . The advancement of p u b e r t y i n wild unqulates under

c o n d i t i o n s of captivity is l i k e l y due to t h e e ~ r i c h e d d i e t s

e lncoua te red t h e r e , It is well e s t a b l i s h e d that the body u e i q h t

and n u t r i t i o n a l status 0 5 a f e ~ a l e i n f l u e n c e the onset o f

p u b e r t y in s h e e p 10v js a f i e ~ f (Dyr~undsson 1973) and

b l a c k - t a i l e d d e e r (Mp;c_i1eus Bemion= ~ g & ~ b i a n g s ) {Hueller E

S a d l e i r 1979, Seip ' f979) , hlthouqh s e a s o n of birth is a l s o known

t o affect p u b e r t y a t t a i n a e n t i n d a n e s t i c s h e e p [Hawker & Kennedy

1978) t h e effect of t ira inq vould be minirtiiaed i n an animal s u c h

as bighorn sheep with a narrow s e a s o n of b i r t h [ B u n n e l l 3 9 8 0 ) . A

population of bighorns on a poor n u t r i t h n a l $lane miqht

e x p e r i e n c e a d e l a y i n p u b e r t y ,

Coop f 3966) d e m o n s t r a t e d i n d o a t e s t i c sheep that o v u l a t i o n

r a t e is dependent upon body mass of the female a t t h e t i w o f

m a t i n g and upon whether the plane of nutrition is r i s i n q a t that

time { f l u s h i n q ) , C o n d i t i o n alone, a t tilae of ~ttaiinq, can have a

s i q n i f i c a n t effect upon owuLat ion and s u b s e q u e n t f a ~ b i n q r a t e s

(•’?astiman 9972, Braaley a & . 1975) . T h e a u k f i t i o n d l plane of

itiosl northern wi ld u n q u l a t e s vou la p r o b a b l y be declininq i n

autumn prior t o t h e r u t hence f l u s h i n g i s a very unlikely

o c c g r a n c e (Verpte 1974) .

Berme (1967) h a s d e m o n s t r a t e d for w h i t e - t a i l e d deer

(0docoikus v h x i n i a n a s ) t h a t t h e physical, c o n d i t i o n o f does i n

a u t u a n i n f l u e n c e s l a a b i n q rate, Hitche l l (1973) a n d H i t c h e l 2 32

a f . f 1376) workinq with r ed deer [Eervas elaphus) in S c o t l a n d - h a v e found a d i r e c t r e l a t i o n s h i p be tween a h i n d ' s c o n d i t i o n i n

a u t u n n a n d h e r o v u l a t i o n and preqnancg rates, Females which

s u c k l e d a calf t h e precedinq sunmer [ m i l k hinds) were i n poorer

condition a n d had s i q n i f i c a n t l y f e w e r o v u l a t i o n s t h a n feaales

which did not raise a c a l f f y e l d Binds) the previous sunaaser,

Thus t h e r e p r o d u c t i v e and n u t r i t i o n a l history of a' f e m a l e

d i c t a t e d , t o a c e r t a i n e x t e n t , h e r s u b s e q u e n t r e p r o d u c t i v e

performance. A s i a i l a r p a t t e r n h a s been s u q q e s t e d for mule deer

[Salvasser & & 1 9 7 8 ) a n d c a r i b o u ( R a n d k r tarandas)

{Dauphine 1 976) ,

T h e r e are few p u b l i s h e d accounts r e i a t i n q t h e condition of

e v e s and f e p r o d u c t i v e p e s f o r a a n c e i n b i q h o r n sheep, Herkmer

(1 938) f o u n d axternate year breedinq i n Dallts s h e e p (Qvis da2AA

dal1&f on poor range i n Alaska,

H u l t i p l e o v u l a t i o n s d o n o t a p p e a r t o be coimon i n bighorn

sheep as t v i n n i n q is a rare o c c u r a a c e fEccZes G S h a c k l e t o n

1879) . Hence i t uoufd a p p e a r tha* this i s n o t a n i l n p o r t a n t

o p t i o n i n the r e p r o d u c t i v e r e p e r t o i r e of biqhorn s h e e p ,

A femle d o m e s t i c s h e e p i n poor body condi t ion stands a

g r e a t e r c h a n c e af e ~ b r y o loss t h a n d o e s a ewe i n qood condition

( G u m E Daney '19731, T h e s e authors also s u g q e s t that c l i ~ a t i c

factors can e x a c e r b a t e t h i s e a r l y embryo wastage, Thorne et, & *

(19761 show t h a t elk {Cervus w a d e n s & ) i n poof condition way

abort t h e i r c a l v e s , D a l l ' s s h e e p on poor ranqe h a v e been shown

t o resorb t h e i r f o e k u s e s {Heiaer 1378), while Pseobrazhensk i i

(1961 as c i t e d i n G e i s t 1971) r e p o r t s r e s o r p t i o n o c c u r s i n q i n

r e i n d e e r t h a t lose body weiqht e a r l y i n q e s t a t i o n .

That b i r t h u e i q h t is in f luenced by a f e x a a l e l s nutritional

s t a t u s h a s been shown f o r d o a e s t i c s h e e p {Lodqe E Heany 1975,

R u s s e l & sf, -3377), elk f'fhorne $t pa, 2976), and w h i t e t a i l e d

deer fVer@e 1977). These n u t r i t i o n a l stresses have t h e i r

q r e a t e s t effect n e a r p a r t u r i t i o n when foe ta l deniands a r e

qreatest fiYloen l 9 ? J ] . The p r o b a b i l i t y of e a r l y n e o n a t e survival

is d i r e c t l y r e l a t e d t o its b i r t h w e i q h t i n d o m e s t i c s h e e p IPfeaker

& Niekerk 19773, elk [Thorne & &. 1376) , and w h i t e t a i l e d deer

f.Odoc=oileus v i r q i g h a n g ~ ) (Verne 1977). An e l k born a t

approx iaate ly I 6 kg would have an e s t i a a t e d 90% p r o b a b i l i t y of

s u r v i v a l %o t nonth whereas a calf b o r n a t less t h a n 11 .4 kq

would have less t h a n a 50% p r o b a b i l i t y of survival, E a r l y

aortal i t7 r a t e s for w h i t e - t a i l e d deer vary between 10 and 7 0 %

for fawns born between 2.25 kq and 3.25 kq. It i s clear that

n u t r i t i o n a l p l a n e and body c o n d i t i o n during l a t e q e s t a t i o n can

h a v e p ro found e f f e c t s upon a feiuale's net r e p r o d u c t i v e success,

b) Diseases and P a r a s i t e s

The ntost well docuraented and severe eaortalitv a q e n t knovn

to a f feet b i q h o r n sheep is the pneuraonia coraplex a s s o c i a t e d with

i n f e s t a t i o n s of t h e i n d i q i n o u s lunqworm p r o t o s & g p ~ ~ l u s spp,

{Buechner 1960, F o r r e s t e r 197 1, S t e l f or !97 l ) , The e t i o l o q y of

t h e p n e u a o n i a c a n i n v o l v e v i r a l , ~ y c o p l a s m a l o r b a c t e r i a l

a q e n t s , often more than one, and i n v a r i a b f y i n a s s o c i a t i o n with

t h e n e s a t a d e ( F o r f e s t e r 1971, P o s t 1 9 4 5 ) , It i s t h o u q h t t h a t She

nematode p r e d i s p o s e s the l u n g s to i n v a s i a n by the pneumonia1

a q e n t s {Anderson 1975) ,

T h e d i s e a s e itself is c h a r a c t e r i z e d i n l a a b s by a n a c u t e

a n d f r e q u e n t l y f a t a l c o u r s e , f n f e c t e d l a a b s t e n d t o couqh

f r e q u e n t l y a n d e x h i b i t l e t h a r g y [Anderson 1975, F o r r e s t e r 19713.

Alttnouqh t h e l a s b s c a n be i n f e c t e d by i n g e s t i n g the i n t e r a e d i a t e

a o f l a s c a n husks , t h e y c a n also b e i n f e c t e d p r e n a t a l l y .

T r a n s p l a c e n t a l i n f e c t i o n has been d e n o n s t r a t e d in both Rocky

Mountain b i q h o r n s [ F o r r e s t e r 8 S e n q e r 135&, Gates E Samuel 7377,

l3ibtPTen: gg 1972) a n d C a l i f o r n i a b i q h o r n s ( K i s t n e r I; P y s e

1979) , T y p i c a l l y , when lungworm - pneumonia complex i s a ma jo r

s o r t a l i t y f a c t o r i n a p o p u l a t i o n , lambzewe r a t i o s are h i q h i n

e a r l y s p r i n q after l ambing and t h e n d e c l i n e i n f a t e summer and

autumn a s i a c l e w e n t wealhes b e q i n s (Crueap 1971, Boodard s$ a&.

1 S?Q) , Laarbs b e q i n -to show s i g n s of p h y s i c a l d e b i l i t a t i o n a n d

c o u q h i n q i n l a t e sumer c o i n c i d e n t a l w i t h t h e i r decline i n

naabers ( f loodard e__t a&, 1972). I n infected h e r d s S h e pneu~onia t e n d s t o take a c h r o n i c

for@ i n a d n l t animals which h a v e s u r v i v e d t h e acute p h a s e as

j u v e n i l e s , These a n i m a l s exhibit l e t h a r q i c behav iour and

i n t e r m i t t e n t c o u q h i n g , e s p e c i a l l y durf ng w i n t e r f F o r r e s ter

1971). I n t b e s o f severe stress, c l i aac t i c o r hvrnaa i n d u c e d ,

the a c u t e for@ Bay r e a p p e a r i n a d u l t s (Pos t 1376) a n d t h e

p o p u l a t i o n a a y e x p e r i e n c e a serious d i e - o f f ( B u e c h n e r 1 360,

S t e l f o x 3 97 1) Even a p p a r e n t l y h a r d y sheep can r a p i d l y succnrab

t o pneumonia i n a h e r d which i s s e v e r e l y s t r e s s e d (Thorne 19711,

However the ef Eects upon r e p r o d u c t i o n of the lunquorm - pneumonia couiplex c a n be more subtle t h a n s i a p l y direc+

a o r t a l i t p of r e p r o d u c t i v e age ewes, S t e l f o x a n d M c G i U i s 11370)

demon s t r a t e d t h a t body w e i g h t o v e r w i n t e r va r i ed i n v e r s e l y n i t h

t h e deqree of lunqworrtt i n f e s t a t i o n , a s n e a s u r e d b y 1st staqe

l a r v a l c o u n t s i n sheep faecal p e l l e t s , As t h i s weiqht l o s s is

p r i m a r i l y i n tissues of enerqy s t o r a q e , t h e amount o f enerqy

a v a i l a b l e t o a ewe for foe ta l p r o d u c t i o n would b e r e d u c e d i n

heavily i n f e s t e d p o p u l a t i o n s , Hence b i r t h w i q h t s o f lambs would

be e x p e c t e d t o b e lower in h e a v i l y i n f e s t e d p o p u l a t i o n s a n d ,

c o n s e q u e n t l y , Zaab s u r v i v a l u o n l d be exgectea t o decline,

E l l e n f i e r q e r f 1976) s u q q e s t e d a sirni lar model t o accoun t for

d e c r e a s e d l a a b s u r v i v a l i n m o d e r a t e t o h e a v i l y infested

p o p , u b a t i o n s durinq y e a r s of p o o r s p r i n g weather when c o m p a r e d

w i t h l i g h t l y i n f e s t e d p o p u l a t i o n s ,

L u n q v o r ~ s o f the g e n u s P r o t ~ s t r o n q v l u s h a v e been found i n

v i r t u a l l y a l l p o p u l a t i o n s o f b i q h o r n sheep i n which t e s t l n q h a s

been c o n d u c t e d ( F o r r e s t e r ? 9 7 1 j , T h i s i n c l u d e s t h e h e r d s i n t h e

a s h n o l a River w a t e r s h e d where faecal a n a l y s e s c a r r i e d o u t i n

1950 and 1972 i n d i c a t e d a r e l a t i v e l y h i g h i n c i d e n c e of

i n f e s t a t i o n {Blood 1963bg C,C, Hlfueller, p e r s , conanr,), Hovever

t h e p n e u ~ o n i a - complex h a s o n l y been o b s e z v e d i n some Bocky

a o u n t a i n b i q b o r n h e r d s and never i n p o p u l a t i o n s o f C a l i f o r n i a

b i q h a r n s f3loisiZ 3963b, F o r r e s t e r 1971), P o s t (1376) speculated

t h a t this p h e n o ~ e n o n ittiqht be associated with t h e h i q h e r

e l e v a t i o n s e x p e r i e n c e d b y Paany Rocky H o u n t a i n h e r d s , T h e severe

c l i n a t i c c o n d i t i o n s e n c o u n t e r e d a t h i g h e l e v a t i o n s p r e d i s p o s e

t h e sheep t o l u n g a s s o c i a t e d d i s e a s e s , Tn British Columbia,

California biqhorns g e n e r a l l y inhabit ranqes a t lower e l e v a t i o n s

than t h o s e ~f Rocky Wountain b i q h o r n s ,

c) P r e d a t o r s

R l t h o u q h p r e d a t o r s are known t o t a k e a o u n t a i n sheep

{ C r o n e a i l l e r 1948, G e i s t 3971, Kennedy 1348, Mur ie 1944) t h e r e

have been f e u of studies d e a o n s t s a t i n g t h a t predation h a s a

~a jor e f f e c t upon p o p u l a k i o n s ize , S t r e e t e r f 197O), a • ’ ter

r e v i e w i n g the a v a i l a b l e l i t e r a t u r e , s u q g e s t e d that p r e d a t i o n

a ra inor n t o r t a l i t y f a c t o r i n b i q h o r n s . Hclaqqart-Cowan f 1979)

s t a ' t e d that, on t h e b a s i s of faecal a n a l y s i s , b i q h a r n s were

u n d e r - r e p r e s e n t e d i n t B e diets of predators i n the Canad ian

national p a r k s , Geist (1971) fe l t t h a t h e a l t h y biqhorr? sheep are

rarely t a k e n by nun-huitian p r e d a t o r s , Suqden ( I 36 1 ) c o n s i d e r e d

t h a t p r e d a t o r s have a rsinor effect on California b i q h o r n

p o p u l a t i o n s in s o u t h e r n B r i t i s h C o l u ~ k t l a .

B iqhorn s h e e p show a p p a r e n t 1 y s u c ~ e s s f ul b e h a v i o u r a l

t a c t i c s when c o n f r a n t e d b~ p r e d a t o r s i n c l u d i n g defensive

qrouping, c o l l e c t i v e conf s o n t a t i o n s w i t h potential. p r e d a t o r s ,

and d e f e n c e of l a ~ b s b y ewes ( B e r q e r 1978a, b, Hornocker 1369,

Shank 1977). These B e h a v i o u r a l p a t t e r n s , coupled with t h e

sheepts t e n d e n c y t o seatain close t o e s c a p e t e r r a i n , tends t o

sake s h e e p relatively inviolate t o p r e d a t i o n ,

Y e t p r e d a t o r c o n t r o l is f r e q u e n t l y one of t h e first

@anagerial tactics u t i l i z e d uhen a n unquf a t e p o p u l a t i o n is

peacceiwed as d e c l i n i n g gHeiaer 1976, Kehsall 1968, Ramsay E S e i p

3979, Rausch G Hinman 3377, Spaldinq 3973) . fhy t h i s s h o u l d b e

so is n o t imraediatly clear. P e r h a p s t h e d r a n a t i c effects which

p r e d a t o r s rap have upon doaestic s h e e p f l o c k s (Henne 1 8 7 7 ) h a v e

been p r o j e c t e d onto wild unqulate heras. Perhaps s t o r i e s s u c h as

that of t h e Kaihab Plateau d e e r herd are i n f l u e n t i a l (Cauqhley

19701. This is n o t to a r g u e t h a t p r e d a t o r s , i n certain

s i t u a t i o n s , c a n n o t and do not s i q n i f i c a n t l y affect p r e y

p o p u l a t i o n s , e s p e c i a l l y af ter these populations have b e e n

reduced b y huaan a c t i v i t y ( 8 e r q e r u d 1979, P a r k e r 1972, Rausch E

Hintaan 1 9 7 7 ) . However changes i n u n g u l a t e p o p u l a t i o n size can

also be due t o p la ta t : h e r b i v o r e i n t e r a c t i o n s (Cauqhlev 1976) .

T h e e f f e c t s of c l i a a t e upon a n ungulate p o p u l a t i o n can be

both subtle and direct , Because m a a a a l s are h o n w o t h e r ~ s they are

free fro@ eta b o l i c dependence upon external h e a t sources, T h u s

i n northern r e g i o n s a d u l t u n g u l a t e s can s u r v i v e s e e m i n g l y

i n i n t i c a l cf i a a t i c c o n d i t i o n s by u t i l i z i n q v a r i o u s b e h a v i o u r a f

and p h y s i o l o q i c a l means (Pfoen 1973, Scha id t -P le i l s en 1975),

Direct aortaf i ty d u e t o weather rarely o c c u r s (Helsall. 1568) ,

However t h e ~ e t a b o l i c c o s t s of n a i n t a i n i n q howothermy u n d e r

adverse c o n d i t i o n s c a n be t r en t endous ly e x p e n s i v e {Hensha u 22 a, 3972, Euen 1373), An a n i m a l , under s e v e r e weather c o n d i t i o n s ,

aust use up i ts body stores a t a n i n c r e a s e d sate, Its

s a i n t e n a n c e r e q u i r e m e n t s are i n c z e a s e d . Qnde r profonqed and

i n t e n s e winter c o n d i t i o n s a n i n c r e a s i n g p r o p o r t i o n of u n s u l a t e s

w i t h i n a p o p u l a t i o n are found i n p m r p h y s i c a l c o n d i t i o n IVerme

6 Ozoga 3971) , Aqain, f e r aa l e s i n a n emaciated c o n d i t i o n a f t e r a

severe w i n t e r t e n d t o g i v e b i r t h t o s a a l l e r o f f s p r i n q w i t h a

r educed p r o b a b i l i t y of s u r v i v a l {Verine 1369, Verne E Ozaqa 187 I ) ,

T h e n u t r i t i o n a l l y s k r e s s e d •’@&ale tends t o c o n v e r t h e r body

stores i n t o o a i n t e n a n c e r e q u i r e m e n t s r a t h e r t h a n i n t o foetal

biallrass.

The actual stressors e x p e r i e n c e d by a n u n g u l a t e i n a h a r s h

v i n t e r are r a u l t i p l e , Lowered a i r t e m p e r a t u r e s Lead to increased

s n e r p r e t i c e x p e n d i t u r e s i n o r d e r t o m a i n t a i n body t e ~ p e r a t u r e .

sJ indcf t iZl factors create a n a d d i t i o n a l e n e r g e t i c bu rden upon t h e

u n q u l a t e , Snowdepth adds further enerqetic costs both for t ravel

and f o r fosaqinq ( G e i s t 1973, Moen 1973). Forage a v a i l a b i l i t y is

i n v e r s e l y r e l a t e d t o increasinq s n o a d e p t h and density I G e i s t

1373, G i l b e r t 24 ~ 2 . 1970). Thus the e f f e c t of a d v e r s e climatic

f a c t o r s upon a d u l t u n g u l a t e s is t o increase e n e r g e t i c

expeni l i tures a n d t o reduce enerqy intake, The effect u p o n

reproductive performance is theref ore sir i lar t o t h o s e f a c t o r s

discussed u n d e r n u t r i t i o n a l i a f l u e n c e s , Nutr i t ional Etresses are

e x a c e r b a t e d by i n i a i c a l . weather,

C E i a a t i c factors can affect a n a n i a a l s n u t r i t i o n a l status

t h r o u g h a direct i n f l u e n c e upon the p l a n t c o n m u n i t i e s , Soil

zt$oistnre, d e g r e e of i n s o l a t i o n and l e n q t h of the q rowinq s e a s o n

can a11 p l a y a sole i n the q u a l i t y a n d q u a n t i t y of f o r a q e

a v a i l a b l e t o the v i P d u n q u l a t e IStoddart 2% 1975). Harper

(1969) o u t l k n e d t h i s very well. for t h e A s h a o h w i n t e r r a n q e s ,

C l i ~ l a t i c effects c a n a l s o influence t h e i n c i d e n c e of

disease within a p o p u l a t i o n , An a n i ~ a f e x p e r i e n c i n q c o n t i n u e d

ex treme t b e r a a l . stress bwoaes i n c r e a s i n q z g s u s c e p t i b l t ; t o

pathoqen ic i n ~ a s i o n by noraal ly b e n i q n a i c r o b e s [ P o s t 1976)

$#hereas c l i ~ a t e aag h a v e an a l t i ~ a t e effect upon a d u l t

u n q p l a t e m o r t a l i t y a n d r e p r o d u c t i v e success, i t c a n have a

p r o x i s a t e effect upon t h e n e o n a t e s , Due t o t h e direct

relationship b e t w e e n surface areazmass rat ia and heat loss,

o r q a n i s m s n i t h small body s ize h a v e qreater d i f f i c u l t y

a a i a t a i n i n q t h e r ~ o r e q u l a t i o n under adverse w i n t e r c o n d i t i o ~ s ,

A l e x a n d e r & 32, 11 359) have shown t h a t the rmal . stress can

s i q n i f i c a n t l y i n c r e a s e e a r l y neonatal r o r t a l i t y i n d o m e s t i c

larsbs. The oaxiroal metabolic rate of t h e n e o n a t e is not

s u f f i c i e n t t o m a i n t a i n body core t e l t l p e r a t u r e , it b e c o n e s

hyprstfiernaic and dies, Hart et &, (1961) and Lentz and Hart

(1960) were able t o show direct m r t a l i t y of c a r i b o u calves d u e

t o t h e c h i l l i n g effects of low t e a p e r a t u r e , w i n d c h i l l and

p r e c i p i t a t i o n .

G e i s t 41973) described lrtountain sheep utilizinq lagabinq

areas o n steep, c o n v o l u t e d s o u t h - f a c i n g sf opes. Such areas cf fer

reduced t h e r ~ a l stress through i&xoelimatic protection,

P r e d a t i o n r i s k wouf d l i k e w i s e be reduce3 i n s u c h sites of b i r t h ,

T h e effect of climate upon l a ~ b i n q i n Dall's sheep was

shown by B u a n e U ( l ! l8Uf , L a b s born e a r l y i n t h e l a m b i n q season

e x p e r i e n c e d a p p r o x i m a t e l y t n i c e t h e mor ta l i ty rate of those born

two weeks later, P o l l o ~ i n q h a r s h winkers S t e l f o x 11975) found

t h a t 3ockp 8oua ta i .n bighorn e v e s e x p e r i e n c e d qreater n e i q h t

l o s e s , h i q h e r l u n q w o r a burdens a n d i n c r e a s e d laiub m o r t a l i t y

t h a n i n s p r i n g s f o l l o w i n q a i l d w i n t e r s ,

Severa l i n v e s t i q a t o r s have a t t e m p t e d t o d e v e l o p indices of

wia,ter severity -for n o r t h e r n s p e c i e s which would h a v e practical

a p p l i c a t r c n t o a a n a g e r s ( P i c t o n 3978, 1973, flerae 1968, Vertni; E

Ozaqa 1971) . e) Stress

This i s rather a c a t c h - a l l c a t a q u r y meaat to zepresenz a l l

t h o s e e x t r i n s i c factors which c o u l d affect t h e r e p r o d u c t i v e

p e r f o r ~ a n c e of a p o p u l a t i o n b u t which do n o t f a l l w i t h i n t h e

a b o v e c a t a q o r i e s , ft s h o u l d Be n o t e d t h a t n u t r i t i o n , climate,

d i s e a s e and p a r a s i t e s are also s - t r e s s o r s i ~ p i n g i n q upon t h e

h o ~ t t o s t a s i s of a ~ o u n t a i n sheep o r o t h e r u n g u l a t e , This new

stress c a t a q o r y s i g h t be labeled p s y c h o f o q i c a l stress, Stress

h a s been p o s t u l a t e d t o p l a y a role i n t h e r e q u l a t i o n o f

p o p u l a t i o n s ize ( C h r i s t i a n E D a v i s 1964) a l t h o u q b its i m ~ o s t a n c e

has been q u e s t i o n e d tKrebs 1964) .

De'Horqe (3376). Ee is t (1971) , and Horejsi (19761 speculate

upon the effects of stress npon h i q h o r n s h e e p , The a u t h o r s

suqqest t h a t p s y c h o l o q i c a l stress c o u l d have a major ef feet upon

big horn p o p u l a t i o n para rae te rs . Hudson (1 972) o b s e r v e d that many

d i s e a s e o u t b r e a k s i n b i q h o r n s are a s s o c i a t e d with some ferm of

e n v f r o n ~ e n t a l stxess, a l t h o u q h t h e evidence i s circunastantial ,

stress is s u g g e s t e d f r e q u e n t l y enough i n these outbreaks to

w a s r e n t f u r t h e r i n v e s t i g a t i o n I n t o its e f f e c t s upon 'wildlife,

However a c t u a l d a t a q u a n t i f y i n g t h e e f f e c t s of

p s y c h o l o q i c a l stress upon f r e e - r a n q i n q u n q u l a t e s is l a c k i a q .

~ a c h r t h u f &A, (1 979) have bequn s t u d i e s monitoring h e a r t ra te

in free-ranqinq biqhorn s h e e p in an ef fort to evaluate t b e

effects of p s y c h o ~ ~ q i c a l stress,

a ~ i u r e prcarala

1 . Ashaola study site

a, fn t h e spring of 1977 and 1978 two c l o v e r traps l C l o v e r

1956) were set up to trap sheep . The traps were b a i t e d

w i t h apple sash, salt, and a l f a l f a hay (Rutherford E

Schmidt 1373, Schmidt 1976) . I n 3377 the t r a p s were

located i n reqion S-4 w h i l e i n 1978 they were l o c a t e d i n

reqioa 5-1 f P i q u r e 5 ) . A t o t a l of 14 d a y s in 1 3 7 7 and 22

days in 1978 were spent t r a p p i n q between February I and

April 15 in e a c h par,

zn $979 a 35' x 358 drop n e t s imi lar to t h a t described

by Schmidt (1976) was s u p p l i e d by the B,C, F i s h and

V i l d l i f e Branch, The net was erected over one of t h e

w i n t e r f e e d f n q s t a t i o n s i n reqion 5-1, The net was

baited with standard s h e e p p e l l e t s { B u c k e r f i e l d s sheep

pellets #324O), T h i s n e t was o p e r a t e d for 29 d a y s

b e t w e e n February 21 and March 21 ,

c. In Apri l of 1979 a Cap-Chur l o n q range imntobiliainq qun

spstela f P a l ~ e r Che~slical and Equipment Co., D o u q l a s v i l l e ,

FIGURE 5 Aer ia l photograph of t h e study s i t e showing t h e census zones

de l imi ted by t h e B r i t i s h Columbia F i sh and Wi ld l i f e Branch.

G e o r q i a f was u s e d t o imsobilize ewes. Ketaset ( K e t a m i n e

h y d r o c h l o r i d e , 100 aq/mf. Roqar/STB Ltd, , P o i n t e C la i r e ,

Q u e b e c ) and Bornpun {Xylaxine h y d r o c h l o r i d e , 100 rq/ml,

Bayve t Corp, , H i s s i s s a u q a , Ont.] were used i n a 1: l

m i x t u r e and a d o s a q e o f 2.2 sq /kg body w e i q h t e a c h t B , C .

F i s h 6 ~ i l d l i f e Branch , s u q q e s t e d d o s e ) , This dosaqe

f a l l s w i t h i n the upper s p e c t r u ~ o f the s u q q e s t e d ranqe

f o r u t i l i z a t i o n of these druys fo r i m o b i l i z a t i o n of

u n q u l a t e s (Hebert E HcPe-t r idqe 2379) . V e i q h t s of ewes

were a s s u a e d t o b e a p p r o x i s a t e h y 50 kq, f C o - o p e r a t i v e

Okanagan B iqho rn Sheep R e s e a r c h Group, unpubLishsd

data) ,

Census methods.

A s t a n d a r d c e n s u s route was t r a v e l l e d , when weather and

s c h e d u l e p e r l a i t l e d , twice a d a y a n d a l l sheep o b s e r v e d were

c o u n t e d and c l a s s i f i e d t o a q e and sex, T i a e o f day and t h e i r

l o c a t i a n s were r e c o r d e d , Care was taken w h i l e f o l l o w i n q the

r o u t e -to min imize h a r a s s m e n t of t h e s h e e p by ny a c t i v i t i e s ,

Hence s t a l k i n g t e c h n i q u e s u s i n q a v a i l a b l e c o v e r and

a v o i d a n c e of s k y l i n e e x p o s u r e were a d o p t e d , I felt t h a t t h i s

would minin ize fliqht induced moveineats of sheep between

c e n s u s areas d u r i n q a c o u n t , C e n s u s d i v i s i o n s are s h o v n i n

Figare 5, The census r o u t e travelled is shown in F i q u r e 5 ,

Both the c e n s n s r o u t e a n d t h e c e n s u s d i v i s i o n s f o l l o w those

of t h e B,C, F i s h and U i P d l i f e s u r v e y s c o n d u c t e d f rom 1970 -

1972 (3, O e b s t e r , unpublished d a t a , Rainsay 1976a). A l l

c e n s u s d i v i s i o n s c o u l d be s e e n •’row a t least one p o i n t on

t h e r o u t e , with t h e exception of certain p o r t i o n s of reqions

5-3 a n d 5-8, Census d i v i s i o n boundaries follow e a s i l y

d e a a r c a t e d p h y s i c a l f e a t u r e s ,

Sheep were o b s e r v e d u s i n q 7 x 35 b i n o c u l a r s and a 15-45

x 60 zam s p o t t i n q telescope,

Several atte~pts h a v e been ~ a d e i n the p a s t , b o t h b y

a y s e l f and t h e B.C, Fish and w i l d l i f e Branch t o observe and

c o u n t laabs a t or soon a f t e r p a r t u r i t i o n , T h e steep and

maqqied t e r r a i n of t h e l ambinq a r e a s h a v e t h w a r t e d a l l

e f f o r t s , For t h i s s t u d y it was felt that e x t e n s i v e human

e x p l o r a t o r y a c t i v i t y on t h e JLarabinq areas d u r i n q t h e na ta l

p e r i o d c o u l d have a severe n e q a t i v e i a p a c t upon latab

survival due to lamb abandonment by ewes a n d t h e p o t e n t i a l

for laab injury while they are a t t e ~ p t i n q t o e s c a p e , Hence

n o attempt was made t o o b s e r v e l a a b s a t t h e time of

p a r t u r i t i o n , nos i n the period iareediat ly af ter p a r t u r i t i o n

when they remain seguestered on t h e lawbinq cliffs,

C e n s u s e s aere aade between A p r i l and J u n e of 1976,

1938, 3979, and 1980, The k i q h e s t c o u n t of e a c h day" cceasus

was w e t 3 i n the p o p u l a t i o n estimates. Count data was

c o l l e c t e d opportunistically d u r i n q the months of April, n a y ,

and June i n the y e a r s 1970 - 1975 and 1977 by B,C, F i s h and

W i l d l i f e personnel , f f 3 ,C , F i s h C U i l d l i f e , unputlLshisd data).

Count d a t a for t h e y e a r s 1970 - 1976 are described i n Ramsay

(3975a] , Coun t s i n t h e y e a r s 1970 - 13972 were ntade by B,

Qebster f o l l o u i n q t h e c e n s u s r o u t e shown i n Fig. 6, The

counts made i n other y e a r s b y t h e B.C. Fish and V i l d l i f e

Branch (2973 - 1375, 3977) were not s t a n d a r d i z e d a s t o

n u ~ b e r of p a s t i c i p e n t s , t o route t r a v e l l e d , n o s t o c e n s u s

p e r i o d , It is assumed that couats a a d e in these years are

co~parible t o t h e c o u n t s a a d e d u r i n q t h i s s t u d y ,

The best e s t i a a t e for t h e total nnsber of sheep i n the

herd e a c h s p r i n g , b u t n o t incPudinq t h e l a ~ b s of the year,

was aade n s i n q t h e bounded c o u n t e e t h o d of Robson a n d

O h i t l u c k ($964) a s r e p o r t e d by O v e r t o n (1371) and Francis

f t 973) , This i s a nun-pasaaetric s t a t i s t i c a l t e c h n i q u e vhich

al lows the e s t i ~ a t i o n of t h e u p p e r bound of t h e size of a

p o p u l a t i o n from a series of c o u n t s of the a n i a a l s within t h e

p o p o h t i o n , Pt is assuasd t h a t , on any one c o u n t , these is a

f i n i t e p o s s i b i l i t y of enunerat lnq a11 of t h e aniwals within

t h e p o p u l a t i o n ,

The b e s t estirxlate of total numbers w i t h i n the 4

p o p u l a t i o n is q i v e n by N = 2fE1,) - H,., where $4, is the

lafqest v a l u e of the series of c o u n t s bi, , N,, NJ,, . . r r N K and

W,,, is t h e s e c o n d h iqhes t : value ,

The 100tt-%)I upper c o n f i d e n c e l i m i t i s approx i sa ted by

, IN, - Hk-, 1 f l I + N*.

The bounded count estimator a l l o w s a reduction of bias

as s a m p l e sizes i n c r e a s e , T h i s atethod of t o t a l c o u n t

e s t i m a t i o n u a s chosen because o f the l i m i t a t i o n s of qround

c e n s u s @&hods i n o b s e r v i n q all of the sheep on t h e r a n g e a t

a n y one time and t h e for& of the d a t a c o l l e c t e d i n years

prior t o this study.

3 , W i n t e r f e e d ~ a n i p u l a t i o n s ,

S t a n d a r d sheep protein pellets (Sheep p e l l e t s # 3240,

Buckerfields, Ltd , , Vancouver, 3 ,C . f were p l a c e d o u t on

Sou th S l o p e d u r i n g t h e w i n t e r s of 1977 - 1980 a s pa r t s f a

S.C. Fish a n d B i l d l i f e m a n a q e r i a l psoqram. The cornpos i t ion

of t h i s f e e d is given i n Appendix 1,

In the w i n t e r of 3477/78 5Q5 kg of p e l l e t s were p l a c e d

o u t b e t w e e n Noveaber 4, 1377 and Ray 95, 1978 i n regions 3- 1

a n d 5-5, 300 Bq of p e l l e t s were p l a c e d out between March f

and gay 35 7979 in reqion S-3, P i n a l l y Y O 0 kq o f p e l l e t s

were p l a c e 3 out in r e q i o n 5-3 and 400 kq i n r e g i o n 5-5

between November 6, 1979 and EIarch 3 , 1980,

I n each o f t h e t h r e e oiaters in which feedinq tcok

p l a c e 23 kq of CIanizole (6.6% thr iabendazole , Merck S h a r p E

Dohme, Ltd , , K i r k l a a d , Quebec) a n t i - h e l m i n t h i c cpnpound n a s

p l a c e d out w i t h the f eed ,

Q Binter s e v e r i t y index .

C l i m a t o l o q i c a l d a t a (Atwospher ic Division, Envi ronrnent

Canada) for Keremaeos ( e f e a . 435 R, sosle 1150 m lower t h a n

t h e m i d - e l e v a t i o n on S o u t h Slope, a n d a p p r o x i m a t e l y 16,5 ka

I% of s t u d y si te) was u s e d t o d e v e l o p a c r u d e i n d e x of

w i n t e r s e v e r i t y , Al though t h e a c t u a l c l imt i c f a c t o r s w h i c h

c o n t r o l t h e s u b j e c t i v e degree of s e v e r i t y of a w i n t e r f o r a

biqhorn s h e e p are n o t known i n a q u a n t i t a t i v e f a s h i o n i t i s

n o t u n r e a s o n a b f e t o c o n s i d e r w i n t e r t e a p e r a t u r e and

p r e c i p i t a t i o n a s i x i p a r t a n t ( G e i s t 1971, Eloen 39731 . H a r p e r (1 369) a n d Schef f l er 139733 d i s c u s s t h e

i a e t e o r o l o g p of t h e study r e g i o n and show t h a t , a l t h o u q h

p r e c i p i t a t i o n i n c r e a s e s a n d t e m p e r a t u r e d e c r e a s e s uith a n

i n c r e a s e i n a l t i t u d e , there i s a c o r r e l a t i o n between the

c l i ~ a t e a t K e r e a e o s and t h a t h i q h e r i n the s u r r o u n d i a q

a o u n t a i n s .

Lsnq teraa 11343 - 1970) Beans a t Keremeos for meari

d a i l y t e a p e r a t u r e and t o t a l a o n t h l y p r e c i p i t a t i o n for t h e

a o n t h s of J a n u a r y t h r o u q h Hay were used a s the b a s e l i n e for

the index, F o r each year, 1970 - 1980, the mean d a i l y

t e a p e r a t u r e and t o t a l m n t h l y p r e c i p i t a t i o n for t h o s e months

were compared u i t h the l o n g - t e r a aean d a t a , A month that was

aarmr or d r i e r t h a n t h e c o r r e s p o n d i n q long-tem Bean was

s c o r e d + I + ?i cooler or u e t t e r month was s c o r e d - 1 , A month

i n which t e a p e r a t u r e a n d / o r p r e c i p i t a t i o n d i f f e r e d fro% t h e

l s n q - t e r a mean by Bore t h a n 3 s t a n d a r d d e v i a t i o n f o r that

, p a r a ~ l e t e r was s c o r e d an a d d i t i o n a l + or - 1 f f or each

s t a n d a r d d e v i a t i o n above or below 1 s t a n d a r d d e v i a t i o n ) .

Equa l n e i q h t i n q was qiven to b o t h t e ~ p e r a t u f e and

p r e c i p i t a t i o n . Scores f o r e a c h y e a r were suamrd and the

r e s u l t i n g t o t a l was c o n s i a e f e d t h e index for winter

s e v e r i t y , R score of z e r o would represent a3 a v e r a q e winter

u h e r e a s p o s i t i v e scores would i n d i c a t e i n c r e a s i n q l v m i l d e r

w i n t e r s with the c o n v e r s e fo f w i n t e r s givexi n e q a t i v e scores,

5, F a e c a l s m p h collections,

a, s h e e p faecal s a a p l e s

T h e s e were c o l l e c t e d i e m d i a l e l y a f t e r v o i d i n s froin

sheep of kaoun aqe and sex, C o l l e c t i o n s were made durinq

April, Bay, a n d J u n e of 3978 and 2979. F a e c e s were

p l a c e d i n p a p e r bags, labelled, and air d r i e d , S a n p l e s

u e r e later a n a l y s e d for n u a b e r s 0 5 ggtostrongy- s p p ,

l a r v a e per: graH o f dried f a e c e s us inq a ntodified

Baermane f u n n e l t e c h n i q u e (Forrester 197 I ) ,

b P r e d a t o r s a m p l e c o l 2 e c t i o n s ,

Predator faecal s a ~ p l e s were coXlected

o p p o r t u n i s t i c a l l y d u r i n g A p r i l and Bay of 1978 acd 1979

and a i r dr ied in p a p e r bags, S u b s e q u e n t l y rehydra ted and

aacerated s a n p l e s were assayed f o r b i g h o r n s h e e p h a i r ,

Biqharn s h e e p hair s a m p l e s f a r c o a p a r i s o n were o b t a i n e d

f r o m c a p t i v e s h e e p a t the U n i v e r s i t y of British

Columbia, E u l e deer h a i r s a m p l e s were o b t a i n e d from deer

i n c a p t i v i t y a t S i a o n F r a s e r U n i v e r s i t y . Hairs uere

i d e n t i f i e d f o l l o w i n q Boore & a1, ( 3 3 7 Y ) .

Ashnola s t u d y site

In 1977 and 1378 no s h e e p were c a p t u r e d i n t h e Cfovef

t r a p s , Blthouqh t h e sheep would follow the b a i t t r a i l s u p t o t h e

traps, they would not enter i n t o t h e e ,

I n c o n t r a s t t h e B,C, P i s h and g i l d l i f e Branch, u s i n q a

Clover t r a p , conducted a s u c c e s s f u l t r a p p i n g o p e r a t i o n o n t h e

same herd i n aarch and Bay of 4972, The t r a p was baited with

a l f a l f a and s a l t , B total of 5 s h e e p were trapped i n March and 5

s h e e p i n May, Xi is n o t knaun why t h e r e s h o u l d b e such a

d i s p a r i t y i n t rapp ing s u c c e s s between 3972 aad I 9 3 8 / t 97 9, C .C.

g u e l l e r t p e r s , coma,) suqqested t h a t t h e u i n t e s of '1971/72 was

such Bore sevese than t h a t of 1977/78 and 1978/79, @ h e r e a s d e e p

snow conditions and c o l d teapeacat ares vese recorded for the

study site i n 1972 f B , f e b s t e r , unpubl i shed d a t a ) in the late

F e b r u a r y , It may b e t h a t the s h e e p were unde r more s e v e r e

n u t r i t i o n a l . stress i n 1972 and were therefore more likely t o

e n t e r a t r a p unde r f e e d - b a i t i n d u c e m n t , Some effects of u e a t h e r

upon t h e s h e e p and t h e s e v e r i t y of w i n t e r s d u r i n q t h e 1970 's i s

d i s c u s s e d below, Snpp lemen ta1 f e e d i n q d u r i n g the winter of

1877/78 had the effect o f r e d u c i n q t h e n u t r i t i o n a l stress o f t h e

sheep and h e n c e rainirrtizinq t h e a t t r a c t i v e n e s s of t h e t r a p Bait,

T h e Lack of c a p t u r e s u c c e s s i n 1977 and I978 r e s u l t e d i n a

r e v i s i o n of the o r i q i n a l p r o j e c t . It was d e c i d e d i n 1 9 1 3 to:

1, a t t e a p t ta t rap t h e F l a t i r a n h e r d w i t h a d r o p - n e t s y s t e m

similar to t h a t which h a d b e e n used w i t h s u c c e s s b y B.C,

F i s h a n d g i l d l i f e p e r s o n n e l t r a p p i n g on the Vaseaux Lake

b i q h o r n w i n t e r r a n q e s i n the s o u t h e r n okanaqan V a l l e y i n

3977 11% s h e e p t r a p p e d ) and 1378 (16 s h e e p t r a p p e d ) arid to;

2, work i n c o n j u n c t i o n u i t h t h e C o - o p e r a t i v e Okanaqan Biqhora

Sheep R e s e a r c h Group i n v o l v e d i n a f o r t h e r trappiaq

o p e r a t i o n o n t h e Vaseaux Lake w i n t e r r a n q e , Sbeep c a p t u r e d

h e r e would be used a s a c o n t i n g e n c y o r back-up research

s t u d y , Sheep would be t a q g e d , b l o d s a g p l e d , and r e l e a s e d

back into t h e p o p u l a t i o n , Wence p r e g n a n c y rate and e a r l y

p o s t - n a t a l ~ o r t a l i t y l e v e l s c o u l d be d e t e r m i n e d as o u t l i n e d

for t h e ff a t i r o n p o p u l t i o n .

3, If b o t h of t h e a b o v e f a i l e d f d e c i d e d to a t t e m p t t o

. irartlobilize ewes a t lttp pr imary s t u d y site u s i n q t h e Cap-Chur

qun s y s t e a and a c o m b i n a t i o n of the d r u q s K e t a s e t and

R o ~ p u n , S i in i l a r ly , B,C, Fish and a i l d l i f e personnel would

u s e the s a n e equ ipmen t to a t t e r n p t t o iliiatiobilize sheer o n t h e

Vaseaux Lake ranges,

I n I979 no s h e e p were trapped with t h e d r o p net i n t h e

F l a t i r o n band, As with t h e C l o v e r t r a p s used t h e tuo precedinq

y e a r s , t h e sheep would not enter undel: the n e t d u r i n q t h e 2 9

d a y s of t r a p p i n q , As i n 1973 and 1978 the w i n t e r was quite anild

w i t h a l l s n c v qone froa Sou th S l o p e by Basch 15, Supplementary

w i n t e r f e e d i n g may have r e d u c e d t h e ewe * s n u t r i t i o n a l d e wands

d u r i n q t h a t w i n t e r and hence t h e i r u i l l i n q n e s s to Rove under t h e

net,

#. Heiaer ( p a r s , coaaa,) , working w i t h D a l l " sheep i n

Alaska, h a s had sintilar e x p e r i e n c e s w h i l e t r y i n q t o t r a p remote

b a n d s of sheep, %heseas sheep bands that were habituated to

bunan p r e s e n c e would enter t r a p - d e v i c e s , naive sheep would never

enter a t r a p , H e found t h a t the only s u i t a b l e t r a p p i n q system

invalved t h e use of a rocket net, shouinq feu obvious inan-made

s t r u c t u r e s , a t a natural sheep a i n e r a l l i c k .

It a i q h l be n o t e d i n c a n j u n c t i o n vith t h e s u c c e s s of t h e

d r o p - n e t t i n q sys tent a t Vaseaur Lake i n 1977 and 1978 . t h a t the

biqhorn winter ranqes t h e r e l i e w i t h i n 1 kn of a major h i s h n a y

(Huy, # 971, F u r t h e r , a well t r a v e l l e d qravel road passes

t h r o u g h t h e r i n t e r r a n g e , the h e r d is a well known and visited

a t t r a c t i o n for local people, and a winter E e e d i n q proqram had

been c o n d u c t e d a t t h a t site f o r itiaay years pr io r t o t h e

t r a p p i n q . The s h e e p a p p e a r t o be s u c h Bore h a b i t u a t e d to human

beinqs @q/ they can be a p p r o a c h e d sore c lose lp ) t h a n t h o s e o f

the Ashnola he rd ,

Vaseaux Lake c a p t u r e p r o q r a a

The Baseaux Lake drop n e t t i n g o p e r a t i o n was c a r r i e d o u t i n

F e b r u a r y of 397'3, On t h i s o c c a s i o n t h e t r a p s i t s was s a b o t a q e d

by person or p e r s o n s unknown s p i l l i n q s i q n i f d c a n t w a n t i t ies o f

kerosene upon t h e b a i t , t r a p s i k e and drop net, The s a b o t a q e

o c c u r r e d af ter t h e n e t was set up b u t b e f o r e t h e o p e r a t i o n

beqan, A s a c o n s e q u e n c e no s h e e p e n t e r e d u n d e r t h e n e t and no

s h e e p were t r a p p e d i n 1379.

F o l l o v i n q t h e f a i l u r e o f the d r o p n e t o p e r a t i o n a n

i ~ a o b i l i z a t i o n o p e r a t i o n was c a r r i e d o u t a t Vaseaux Lake winter

r a n g e by B,C. Fish and g i l d l i f e p e r s o n n e l . T h i s a l s o was

U A S U C C ~ S S ~ U ~ ,

C o n s e q u e n t l y n o s h e e p from t h e Vaseaux h e r d were taqqed and

s a ~ p l e d i n 1979, T h i s he rd was t o h a v e m d e up ray backup

research p o p u l a t i o n i f c a p t u r e o p e r a t i o n s were aqain

a n s u c c e s s f u l i n 1979 i n the Ashnola . The ease of c a p t u r e of

s h e e p from Vaseavx i n 1977 and 1978 s u q q e s t e d t h a t the backup

p l a n had a h i g h p r o b a b i l i t y o f b e i n q s u c c e s s f u l .

After t h e failure of t h e Baseaux operation and ~y onn

d r o p n e t t i w q p r o q r a a i t was d e c i d e d t o attempt to i~mobilize

ewes i n t h e Asbnula u s i n q t h e Cap-Char qun s y s t e m ,

The u s e o f i a ~ o b i l i z i n q d r u q s was adopted a s a l a s t resort

for sheep c a p t u r e , The d a n q e r s t o t h e a n i m a l s froin t i s s u e t r a u ~ a

fro@ the d a r t s , p o s s i b l e d r u g co lap i ica lc ions , and p r o l o n g e d

i n c a p a c i t a n c e from t h e d r u q s a r q u e d a g a i n s t dsuq use i f

a l t e r n a t i v e trapginq ~ e t h o d s were p o s s i b l e , I n a a s c h of 1979 t h e

d r o p n e t was d i s m a n t l e d , a s t h e s h e e p no lonqer e v e n a p p r o a c h e d

i t , and a d a s t i n q p s o g r a a begun,

Because of the d a n q e r of stress i n d u c e d a b o r t i o n in late

q e s t a t i o n i t was d e c i d e d to d i s c o n t i n u e t h e whole capture

o p e r a t i o n b y t h e first week i n Apri f , The u s e of Rornpun i n late

g e s t a t i o n i n u n q u l a t e s i s i n a d v i s a b l e d u e t o p o s s i b l e a b o r t i o n

i n a u c i n q p r o p e r t i e s (Kniqht 1980, Sadleir, pers. COB&, ) . F i v e days of d a r t i n q were c a r r i e d o u t aur ing l a t e ffarch, A ,

t o t a l of 5 eves were s t r u c k uith d a r t s i n t h e h i n d q n a r t e s s , 811

s h o t s were aade between 20 a ~ d 30 metres, Two of t h e ewes showed

no apparent s i q n s of druq i n f l u e r a c e even after 4 hours . I n b o t h

cases tbe d a r t was s e e n to s t r i k e a n d was s u b s e q u e n t l y o b s e r v e d

p r o j e c t i n g fsos the aaintal, Two ewes showed d e f i n a t e druq

i n d u c e d effects ataxia and d i s t s r i e n t a t i o n ) w i t h i n 3 hour

of i n j e c t i o n , However n e i t h e r animal a l l o w e d a close enouqh

approach t o effect c a p t u r e . One of these ewes uas moni tored fo r

5.5 hours af te r i n j e c t i o n , t h e o t h e r far 3,75 hour s . On both

o c c a s i o n s d a r k n e s s p r o h i b i t e d f u r t h e r o b s e r v a t i o n s . Mo s i q n of

i n c a p a c i t a t i o n was obse rved , S e v e r a l o f t h e s e d a r t e d ewes were

s e e n fo r som d a y s af ter d a r t i n q w i t h the d a r t s still a t t a c h e d ,

On B a r c h 27 a s i n q l e ewe was c a p t u r e d after i n j e c t i o n .

I n d u c t i o n t i se w i t s 3 hou r s . Upon c a p t u r e t h e ewe was f i t t e d with

a b l i n d f o l d to r e d u c e stress and s t r u q g l e (Franzmann 1 9 7 2 ) , +,he

d a r t was r e ~ o v e d a n d t h e wound treated, Even with the b l i n d k o l d

t h e f e n a l e a a d a r e q u l a r a t t e m p t s t o e s c a p e , She was f i t t e d w i t h

a neck band f & r i c k s o n 1979) l a b e l l e d * Z s and a s i n q l e blood

s a a p l e was r e a o v e d from the j u g u l a r v e i n , Bs I was u o r k i n q

alone, f u r t h e r t a g q i n q and s a a p x i n q was n o t c a r r i e d out, T h e

a q i t a t e d c o n d i t i o n o f t h e ewe p r e c l u d e d a n y f u r t h e r

m a n i p u l a t i o n s ,

The se rum sarap le gas s u b s e q u e n t l y a s s a y e d f o r t o t a l

p r o q e s t i n s , The value obtained of 8.5 nqfa l i n d i c a t e d t h a t ewe

* Z * was p r e g n a n t {RaQsay 6 S a d l e i r 1979),

Approx ima te ly 6 h o u r s a f t e r i n d u c t i o n I r e m v e d the

b l i n d f o l d a n d r e l e a s e d * Z a , S h e i n ~ e d i a t l y ran dovn s l o p e ,

s o m u h a t u n s t e a d i l y , a n d o u t o f a y s i g h t , She was then n o t seen

f o r 24 h o u r s , a t which t i n e s h e was o b s e r v e d r u n n i n q n e s t t o

e a s t across lower S-1. B w e '2' was s u b s e q u e n t l y s e e n e v e r y

c e n s u s day u n t i l l a t e June, 3979, F r e q u e n t l y s h e would be s e e n

by h e r s e l f , a n uncontmn o c c u r a n c e i n t h e a d u l t ewes of the

Ash,nola ( p e r s , obs . ) , On J u l y 11 s h e was o b s e r v e d l e a d i a q a n d

s u c k l i n q a lamb, S h e was last s e e n J u l y 15 w i t h a qroup of ewes

a n d lambs, T h i s e v e was n o t seen on trips to the study si2e i n

Auqusk a n d O c t o b e r 1979, n o r o n Barch , Apr i l , and J u n e 1980,

B c a p t u r e rate of 20% d i c t a t e d a n end t o the a a r t i n q

psoqram, P fel t t h a t t h e p o t e n t i a l harm of c o n t i n u e d d a r t i n q

w i t h o u t b e i n q a b l e t o r e a o v e d a r t s f rom non-cap tu red sheep n o r

t o treat the a n i m a l w i t h p e n i c i l l i n w a r r e n t e d s toppinq t h e

proqraxa o n h u m a n i t a r i a n qrounds,

P o ~ u l a t i o n Chanqes

Ground c o u n t s

R e s u l t s of the d a i l y q round c o u n t s of t h e Ashnola s h e e p for

1978, 1979, a n d 1980 are g i v e n i n Table 1, It will be n o t e d t h a t

t h e d a i l y n u a b e r of s h e e p o b s e r v e d f l u c t u a t e d w ide ly , T h e

t o p o q r a p h y af t h e w i n t e r r a n q e a n d t h e behaviour of t h e sheep

contribute t o t h i s phenomenon, Daily mooenents of t h e sheep can

r e s u l t i n l a r q e n u a b e r s of the# q r a z i n q or beddirnq i n a r e a s

which c a n n o t be s e e n f r o @ the c e n s u s r o u t e . I h a v e o b s e r v e d a s

m a y as 40 s h e e p move i n t o view fro& a small draw iats which I

c o u l d n o t see,

Baas t e n d t o use t h e e a s t e r l y p o r t i o n of S o u t h S l o p e ,

Table 1 Daily counts o f sheep numbers from t h e Ashnola s tudy s i t e

f o r t h e yea r s 1978 - 1980.

a) Counts f o r 1978.

Date Ewes Lambs Year l ings Rams To ta l (+ Lambs)

b) Counts f o r 1979.

Date Ewes Lambs Yearlings 2 Y r . 014s Rams Total (+ Lambs)

1979 (cont.)

Date Ewes Lambs Yearlings 2 Yr. Olds Rams Total (+ Lambs)

c) Counts for 1980.

Date Ewes Lambs Yearlings 2 Yr. Olas Rams Total (+ Lambs)

i n c l u d i n q reqion CR, almost exclusively i n the s p r i n q , e a r l y in,

s p r i n q t h e r a m s beqirt. to d r i f t even further east t o u t i l i z e t h e

q r a s s l a n d s found there, APthouqh n o t p a r t of t h e census route,

t h e s e ranqe s vere s u r v e y e d a p p r o x i s a t e l y once e v e r y second w e e k

during sprinq and early suamer, Ewes and juveniles were n e v e r

seen on t h e s e eastern r a n q e s b e f o r e July 15, However movements

of rants b a c k and forth i n and o u t of t h e c e n s u s a r e a ca.n account

fox part of the daily count f l u c t u a t i o n s ,

ft can also be d e t e c t e d f ronn Table 1 t h a t coincident with

the la~bing season, a p p r o x i a a t e l y Hay t - June 1 , t h e d a i l y

number of ewes observed decreases, r i s i n q a q a i n in June. T h i s Is

due to the i m m e d i a t l y p r e - p a r t o r i e n t f e ~ a l e s sequesteriaq

t h e n s e l v e s on the lambinq c l i f fs a n d r e m a i n i n g there for several

d a y s p o s t p a r t u s ,

Population size es t i~ates

The best estimates for pupafation s i z e of the band

winler inq east of t h e Ashnola River are shown i n P i q u s e 7, It is

clear t h a t there has been no increase in population s i ze since

197C, By previous c o n c l u s i o n f9alstsiiy 7376a) that tbe p o p u f a t i o n

was s t a b l e or s l o w l y d e c l i n i n q was born out by data collected

after 1377.

FIGURE 7 Best estimates for population size, with 95% confidence

intervals, for study herd (1970 - 1980). Data for 1970 - 1975 and 1977 are from unpublished B.C. Fish and Wildlife

records. Data for 1976 from Ramsay C1976a). The skewed

distribution of the confidence intervals is a result of the

bounded count method as described on page 34.

TOTAL NUMBER OF SHEEP

T h e r e have been c h a n q e s i n some c h a r a c t e r i s t i c s of t h e

p o p u l a t i o n i n t h e period 1970-1980, T a b l e 2 lists the best

e s t i m a t e s of total population size for e a c h of t h e 1 1 y e a r s .

Also listed are t h e iaaxirxtum number of ewes and Ealnbs c o n n t e d i n

e a c h of t h o s e years. Whereas the p r o p o r t i o n of the number o f

ewes w i t h i n t h e p o p u l a t i o n h a s remained r e l a t i v e 1 y constant, the

l a ~ t b : e w e r a t i o h a s increased markedly in the last 3 years and

will be discussed below,

T h e c h a n q e s i n p o p u l a t i o n p a r a m e t e x s seen a f t e r 1977

c o i n c i d e d with the ~ a n a g e ~ n e n t - i n d u c e d a l t e r a t i o n s of t h e

env i rona t en t begun i n the la te 197O8s, The supplemental f e e d i n q

progralit and anti-helmintic d r u g treatrstent h q a n i n the v i a t e ~ o f

1977, S p r i n g r a n q e b u r n i n q began i n 1976. The druq altld f e e d i n q

proqran was c a r r i e d o u t by t h e Keremeos-Cawston S p o r t s i n e n t s

A s s o c i a t i o n under t h e d i r e c t i o n o f t h e B,C, Fish and g i l d l i f e

Branch, B u r n i n q was c o n d u c t e d by the branch itself, The "iiinq

and aode of a p p l i c a t i o n of t h e s e p e r t u r b a k i o a s were conducted

without i n p u t fsora mysel f , I was t h e r e f o r e unable to r e q u l a t e

t h e nuaber of v a r i a b l e s uhich were altered i n each y e a r , However

i n t h e w i n t e r of 3978/79 I was able t o m a n i p u l a t e t h e t i n i n q of

s u p p l e ~ e n t a l feed a p p l i c a t i o n and the amount p l a c e d out.

Table 2 California bighorn sheep spring census data from the Ashnola

study site (1970 - 1980).

Estimate of Total Maximum Maximum Proportion of Year Number of Sheep Number Number Lamb:Ewe Ewes

(Not Including of of Ratio Within Lambs) Ewes Lambs Population

* B.C. Fish and Wildlife Data

Tuinninq and repeat breedinq

During May and early June of 1979 a ewe s u c h l i n q 2 latnbs

#as observed an several o c c a s i o n s , The ewe had a d i s t i n c t i v e

pelaqe a o u l t p a t t e r n w h i c h f a c i l i t a t e d i d e n t i f i c a t i o n , The l a ~ b s

were n o t i c e a b l y smaller, a t t h a t tiate, t h a n other lambs i n the

herd, It is n o t known whether their size was due to a l a t e r

b i r t h d a t e or to a smaller b i r t h size, It i s known t h a t d o ~ e s t i c

s h e e p t w i n s are born a t a s i q n i f i c a n t l y s m a l l e r birth w e i q h t

than s i n g l e t o n s {Speddinq 1 970) .

I n Bay of 1978 a s i n g l e dayes &serrations of a ewe

s u c k l i n q 2 lambs was made, As i n 4979, t h e lambs a p p e a r e d

smaller than their p e e r s , The e v e could n o t be i d e n t i f i e d with

c e r t a i n t y a n d double s u c k l i n q was n o t seen aqain that year.

TwLnniaq is rare in Biqhorn sheep and se ldom reported,

Bowever t h e one pupalation i n which t u i n n i a q i s dacuoaented is i n

t h e V a s e a u x L a k e herd ~ E E C ~ S 8 S h a c k l e t o n 1979, S p a l d i n q 1965) ,

There may have been aowement of sheep h i s t o r i c a l l y between t h e s e

2 p o p u l a t i o n s (Suqden 1961). Thus i t Ls n o t i n c o n c e i v a b l e , i f

tvinainq has a qeaetic component, that t h e propensity for

t w i n n i n g may alsa B e found i n the Ashnola p o p u l a t i o n s ,

O v e s v i n t e r h a ~ b snrvivai rates

The survival rate of 3ainbs t o aqe 1 is shown in Table 3.

Eambs b o r n i n 1977 had access to winter feed and a n t i - h e l w i n z h i c

d r u q durinq their f i rs t w i n t e r , Lanbs which were born i n I978

a n d $979 were also exposed t o w i n t e r feed i n their f i r s t wineer

and, a s well. their i na the r ' s had access Lo t h e feed durinq t h e i r

gestation.

The s u r v i v a l rates of 370% for 3977 - 1978 and 307% for

t 978 - 1979 are c lear ly incorrect, E i ther these was an error

~ a d e i n the l a & b / y e a r l i n q c o u n t s o r t h e r e was an i n f l u x of younq

s h e e p frog a n o t h e r p o p u l a t i o n , Yithout o b s e r v a t i o n s from

i d e n t i f i a b l e a n i ~ a l s l i t t l e c a n be s a i d c a n c e r n i n q i m i y ration

i n this h e r d . Houever it should be n o t e d t h a t i n 1977 t h e sheep

count was c o n d u c t e d by B,C, Fish and gildlife personel between

Hay 5 and Hap 3 3 for a t o t a l of o n l y 5 census days, The c o u n t

data i n Table 1 sugqests t h a t some newborn l a n b s are n o t seen

u n t i l a f t e r the rtliddle of May, Further, w i t h only 5 c o u n t i n q

days it is no t i n c o n c e i v a b l e that laabs could have been m i s s e d

due t o s o w of the problems e n c o u n t e r e d i n o b s e r v i n g all t h e

sheep on any one day. The c o u n t for 1977 under-represents the

number of Zaiubs which were b o r n and survived to b e p o t e n t i a l l y

c o u n t e d , T h e c e n s u s d a t a for 1977 Ls der ived fro& t h e fewest

n u a b e r of census d a y s and was t a k e n earlier i n t h e l ambinq

period t h a n a n y other y e a r for t h e period 1970 - 1980, 1:

Table 3 Lamb survival to age one year old (1971 - 1980).

Number of lambs Number of yearlings Percentage of lambs (year n) (year n+l) surviving to year 1

20 (1970) 14 (1971) 70.0

23 (1971) 16 (1972) 69.6

14 (1972) 7 (1973) 50.0

12 (1973) 9 U974) 75.0

20 (1974) 10 (1975) 50.0

10 (1975) 8 (1976) 80.0

16 (1976) 15 (1977) 93.8

* 10 (1977) 17 (1978) 170.0

** 27 (1978) 29 (19791 107.0

** 19 (1979) 18 (1980) 94.7

* Anti-helminthic drug and winter feed available to lambs during

their first winter.

** Anti-helmintic drug and winter feed available to ewes in the winter

prior to lambs' birth. Anti-helminthic drug and winter feed available

to lambs during their first winter.

t h e r e f o r e d e c i d e d t o orit t h e laab d a t a f o r 1977 f ~ Q R subsequent

a n a l y s e s of lamb s u r v i v a l sates,

B u n n e l l ( l % O ] , o b s e r v i n q a l a r q e number of taqqed C a l f ' s

s h e e p , f ound t h a t soae lambs were ~ i s s e d i n spring censuses and

wefe probaD3y born l a t e i n t h e season, In the Ashnola i t may tie

that a small n u ~ b e r o f ewes q i v e b i r t h l a te r i n the summer after

the census period h a s f i n i s h e t l , The b i r t h of ewe q Z a s * lamb in

l a t e June or e a r l y J u l y leads s u p p o r t t o t h i s p r o p o s a l .

An a n a l y s i s of v a r i a n c e c o m p a r i n g yearling survival rates

for y e a r s in which feedinq o c c u r r e d a n d y e a r s i n which i t d i d

n o t , o a i t t i n q the d a t a for l a a b s b o r n i n 1977, indicates a

s i q n i f i c a n t : d i f f e r e n c e f p < 0,05f between t r e a t m e n t s ,

Blood f 3963) and S c h e f f ler (3973) showed that ' b i g h o r n s

tended t o qraae on s l o p e s > 12 d e q r e e s , The manaqed g p r i n q burns

of 1976, 3978, and 1379 took p l a c e i n r e q i o n s 5-2 a n d lower 5-1

which are r e l a t i v e l y f l a t sites on the w i n t e r r a n q e , 1 showed

prepiously (Ragsay t376a) t h a t t h e s e areas r e c e i v e d l i t t l e sheep

u s e in e a r l y s p r i n q * V i n t e r / s p r i a q o b s e r v a t i o n s i n 1978 - 1980

c o n f i r m e d these earlier r e p o r t s , Sheep faecal pellet q r o u p s are

less ctsnrraon on the burned p o r t i o n of t h e rcanqe t h a n on upper

S-1, 5-3, and 5-5, Sheep u s e h a s r ema ined low on t h e f l a t t e r

p o r t i o n s of South S l o p e and the controfled b u r n s appear n o t t o

h a v e not r e s u l t e d i n q r e a e e r use o f these a r e a s .

I n the s p r i n q of 1980 the F i s h a n d B i l d l i f e Branch burned

portions of req io r s s S-Y and 5-7 which Z had o b s e r v e d i n p r e v i o u s

years a s r e c e i v i n g intensive use. Dur inq t h e 1380 s p r i n q c o u n t s

no s h e e p were s e e n u s i n q these recently burned a r e a s . F u t u r e

o b s e z v a t i o n s night i n d i c a t e whether use of these areas h a s

chanqed.

Fiyura 8 shows the l a@b:eue r a t i o s for t h e 11 g e a r p e r i o d ,

The r a t i o s i n y e a r s a f t e r w i n t e r f e e d i n q a r e indicated b y open

circles. Analysis of v a r i a n c e indicates t h a t the difference i n

1antk:eae ratios b e t v e e n y e a r s of supp le l l t en t a l Eeedinq and years

of n o feedinq is s i q n i f i c a n . 2 : (p < 0 , 0 0 5 ) .

D e ~ a f c h i 419651 n o t e d a d e c l i n e i n Pamb:ewe r a t i o s from

0,83 i n 3 960 t o 0.42 i n 1964. T h i s t r e n d a p p a r e n t l y c o n t i n u e d

until t h e 1970's when lambzewe r a t i o s a v e r a q e d 0.20 ( p e r i o d

5970-1977). The increase i n lalab p r o d u c t i o n after 1977 h a s nat

r e c p v e r e d t o t h e l e v e l s o b s e r v e d i n t h e e a r l y 1960's.

FIGURE 8 Larnb:ewe r a t i o s f o r t h e yea r s 1970 - 1980. Open c i r c l e s

r ep resen t years i n which win te r feeding occurred.

LAMB: EWE RATIO

E s t i m a t e s s f supplemental winter feed i n t a k e

I n order t o beternt ine how ~ u c h af t h e w i n t e r feed could

h a v e been consuaed by t h e p r e g n a n t eares i t was necessary t o

o b s e r v e t h e r e l a t i v e d e g r e e of u t i l i z a t i o n of the feeders b y

d i f f e r e n t qroups of sheep, No rams o v e r t h e aqe of 3 - Y years

were e v e r o b s e r v e d u s i n q a f e e d e r , Twenty-one a d u l t ewes acd 14

j u v e n i l e s were t i m d w h i l e f e e d i n g a t t h e f e e d e r s , E w e s f e d fox

a n a v e r a q e of 19.0 ~ i n u t e s / v i s i t while juveniles for 10.1

m i n u t e e / v i s i t , B t- test i n d i c a t e s t h a t t h e s e Beans a r e

s i q n i f i c a a t l y d i f f e r e n t fp < 0.0 1) . Adul t females spend almost

twice as l o n g at t h e feeder d u r i n q each visit. Because 2 4 hou r

watches were n o t c o n d u c t e d on f e e d e r s i t is n o t known with what

f r e q u e n c y e v e s and j u v e n i l e s come to t h e feeders, Hovever most

a d u l t ewes were o b s e r v e d c o e n q t o +,he feeders almost every d a y

on which f e e d was a v a i l a b l e whereas j u v e n i l e s were o b s e r v e d less

r e g u l a r l y a t the f e e d e r s .

Thus based upon t h e s e o b s e r v a t i o n s and for the puhpose of

c a l c u l a t i n q the a a o u n t of supplemntal f e e d c o n s u ~ e d by e a c h

q r o u p of s h e e p I assuised that j u v e n i l e s a te 50% of a e v e ' s

consuiupt ion , o n a daily b a s i s , and t h a t feed was only u t i l i z e d

b y a d u l t feaales a n d j u v e n i l e s . Using t h e e s t i m a t e s f o r the

number of e v e s and j u v e n i l e s w i t h i n t h e p o p u l a t i o n i n each o f

the years of s u p p l e m e n t a l f e e d i n q i t was possible to estimate

t h e a v e r a q e p e r c a p i t a consumpt ion of pellets f o r e a c h of t h e

two g r o u p s u t i l 3 z i n q the feeders, The e s t i m a t e d c o n s u ~ p l i o n of

p e l l e t s by the ewes is shown i n Table 4 , The timinq of t h e

supp lemen ta f . f e e d i n q i s shown i n F i q u r e 9,

If t h e peak 0 5 births clccurincy i n e a r l y May i s assumed {see

T a b l e I f a n d t h e q e s t a t i o n p e r i o d i s 175 d a y s { B l u n t ~t . 1977) then it can Be s e e n that winter feediaq occurred during

t h e l a s t t h i r d of g e s t a t i o a i n 3977/78 and 1378179 b u t n o t

d o r i n q 1379/80. P r o t e i n r e q u i r e a e n t s f o r f o e t a l d e v e l o p a e n t

increase e x p o n e n t i a l l y t h r o u q h q e s t a t i o n {Moen 3 9731, Dur inq t h e

f i n a l 2 months o f g e s t a t i o n a ewe" pprotein d e ~ a n d s i n c r e a s e

from a p p r o r i a r a t e l j r 5 gayday t o 14 qm/day above ma in t enance jlvfoen

1933). It will be n o t e d t h a t the p r o t e i n i n t a k e d e r i v e d from

w i n t e r beel i inq i n b o t h 1377/78 a n d 1378/79 would h a v e

contributed c o n s i d e r a b l y to S h e p r o t e i n r e q u i r e m e n t s of laze

q e s t a t i o n ,

Table 5 lists t h e lonq t e r ~ means f o r mean d a i l y

t e m p e r a t u r e a n d total monthly p r e c i p i t a t i o n t a k e n fro@ Keremeos,

Table 6 lists the w i n t e r s e v e r i t y indices c a l c u l a t e d f r o & these

means*

. f i q u r e 10 i l l u s t r a t e s She r e l a t i o n s h i p between t h e 1amb:eue

ratio for e a c h year 11 930 - 1980) a n d the winter severity i n d e x

Table 4 Determination of mount of additional protein available to ewes

in winters of supplefoental feeding.

Number of days on Kg. of pellets

Winter wfiich supplemental consun&/ over @I. protein/day/? ? feed was available tine period

FIGURE 9 Relationship between times of supplemental winter feeding in

1977 - 1980 and the approximate stage of gestation for the Flatiron herd, Total amount of supplemental feed placed out

is shown for each year.

YEAR

Table 5 Long term (1941 - 1970) means for mean daily temperature (OC) and total precipitation (nun) taken at Keremeos.

JAN FEB MAR APR MAY .

Mean Daily Temp. -3.6 1.0 5.0 10.2 14.9

Standard Deviation 3.9 2.4 1.8 1.4 1.6

Total Monthly Ppt. 28.2 16.5 12.8 16.4 21.1

Standard Deviation 16.5 10.3 9.5 13.8 14.1

. .

Table 6 Winter severity index calculated from differences between 30

year norm meteorological data from Keremeos for MEAN DAILY

TEMPERATURE and TOTAL MONTHLY PRECIPITATION and monthly data

for the study years (1970 - 1980).

Year

1970

1971

1972

1973

1974

1975

1976

1977

1978

1979

1980

Winter Severity Index

+6

0

-7

+4

-2

-13

+1

+2

0

+4

-6

FIGURE 10 elations ship between 1amb:ewe ratio of each year and the

previous winter's severity index for the years 1970 - 1980. Open circles indicate years in which winter feeding

occurred.

LAMB: EWE RATIO

for t h a t y e a r * Aqain open circles r e p r e s e n t years i n which

uiater feediaq uccnrred, A l i n e a r r e q r e s s i o n for years i n which

n o winter f e e d i n g t o o k p l a c e i n d i c a t e s t h a t the 1amb:eve r a t i o s

do n o t vary s i q n i f i c a n t l y u i & b winter severity f p > 0 . 0 5 ) a s t h e

r e q r e s s i o n slope d i d not d i f f e r s i q n i f i c a n t l y from zero,

P o t e n t i a l p r e d a t o r s upon b i g h o r n s i n the ashno la wasershed

inc lude coyotes, c o u g a r , black b e a r (Ursus w i c a . g g ) , bobcat

(m r u f u s ) , and g o l d e n eaqle f&ii.J=p cB.cysaeto,s). Incidence of

p r e d a t i o n within t h e herd i s n o t known a l t h o u q h Blood ( 1 961)

t houqht that i t was l i k e l y low.

Salaples were c o l l e c t e d from coyote (1978 - 2 : 1 9 7 9 - 3)

and black b e a r (1978 - 2 : 1979 - 2) faeces which appeared to b e

recently d e p o s i t e d , In b o t h years the b e a r faeces contained o n l y

p l a n t matter w h i l e the c o y o t e faeces contained no hair of either

s h e e p or d e e r .

Bears sere s e e n f o r a g i n g on t h e winter r a n g e s each s p r i n q

on nueerous o c c a s i o n s , The s h e e p appeared to b e alert t o their

p r e s e n c e and e u e - l a a b bands would usually run for e s c a p e terrain

upon s i q h t l n q a black bear . C o y o t e s were in•’ r e q u e n t l y observed

upon t h e open s l o p e s , a l t h o a g h on 2 o c c a s i o n s i n Bay of 1978 a

s i n g l e coyote was observed pursu ing a qroup of ewes and lambs

f som r e q i o n S- 1 o n t o escape ' t e rra in i n r e q i o a LE. On both

o c c a s i o n s t h e c o y o t e stopped b e f o r e e n t e r i n q t h e steep terrain.

Golden eagles were observed almost d a i l y durinq l a t e A p r i l

and Hay, i n a11 3 years, s o a r i n g over S o n t h Slope. Frequently

t h e y would be seen flyinq p a r a l l e l uith t h e l a ~ b i n q area at

a p p m x i a a t e h y the saae e l e v a t i o n a s the t o p of t h e cliffs a n d

within a fev metres of t h e cliff face, No o b s e r v a t i o n s of e a q l e

pradaaion were s a d e . However on 4 o c c a s i o n s durinq the l a m b i n s

p e r i o d aa eagle was seen ta swoop down Zou o v e r a qroup of

f o r a q i n q ewes with accom&anyinq lambs. The l a ~ b s would r a p i d l y

ran t o w a r d s t h e i r dams w h i l e the ewes would behave i n an

a q i t a t e d Banner, j u ~ p i n q when the b i r d passed o v e r r runninq t o

t h e i r lambs, and shakinq t h e i r h e a d s ,

go c o n q a s or b o b c a t siqn were sighted durinq the s p r i n q

laabinq period, C w q a r t r a c k s u e r e i n f r e q u e n t l y s i a h t e d after

fresh s n o w f a l l dur inq t h e w i n t e r and early sprinq, Wo couqar

faeces were ever found,

Three bighorn k i l l s uere l o c a t e d durinq the s t u d y , In Elay

.of 3976 a ewe, which had been taqqed i n 1972 by El, aebster f #

S T * ) , was f o u n d dead i n r e q i o a 5-5, She had b e e n classified a s

o l d f&/ > 7 years) at the tiw of t a q q i n q . The carcass %as

examined within 35 hours of d e a t h , T e e t h vere worn to w i t h i n 2 - 3 i8r of t h e qum l i n e and iuany vere loose i n their s o c k e t s ,

B o d e s a t e snbcutaneous fat deposits vere p r e s e n t bat visceral fat

d e p ~ t s had been consuiried, The femur bone Barrow was dark r e d and

firm, Both a u d i t o r y c a n a l s were f i l l e d q u i t e f i r i a l y with

Also i n Bay of 1376 the s k e l e t o n of a 3/4 c u r l male was

found on the trail to the west of S t a r v a t i o n F l a t s , There was no

i n d i c a t i o n uf f i ~ v l o n q i t had been dead, althouqh it had not

been t h e r e i n December of 1975,

In early February of 1377 a 319 curl , 7 year o l d male

carcass w i t h 2 cougars feeding on it gas seen by a h e l i c o p t e r

pilot. It was a t a l m o s t the saae l o c a t i o n on reqion S-5 as the

carcass of femle # $ 7 ' had been, fly i n s p e c t i o n of the kill site

revealed o n l y the skull, the rest of the carcass had

di sappeared ,

Table 7 s u m a a r i z e s the incidence of Protostronqylid l a r v a e

in faecal s a m p l e s collected durinq April, Hay, and June of 1978

and 1979, The a n t i - h e l m i n t h i c druq f e e d i n q pragram had bequri i n

t h e winter of 1978. Afthouqh approx imate ly 50% of the yearlinqs

and adults Mere i n f e c t e d , the level of infection was quite low,

Blood t f963b) found t h a t 86% of gear l l inqs and 81 of ewes were

infected in the e a r l y 196f)*s , Huel ler [Pers, coma,) Sound ." ,hat

v i r f u a l l y 100% of a d u l t s and yeaslinqs were infected with

Table 7 Incidence of lungworm (Protostrongylus sp.) infection in Ashnola

bighorn sheep herd.

Host

Mean number of

Number of larvae/gm Percentage

samples faeces (dry weight) in•’ ected

Adult ewes (1978) (1979)

Yearlings (1978) 16 (1979) 6

Lambs (1978) 7 (1979) 3

Dur inq the p e r i o d of March t o May 1960 ~lsod f l 9 6 ! ) n o t e d

l e v e l s of i n f e s t a t i o n in s h e e p o t h e r t h a n lambs o f 10,1

larvae/gtrt dry weiqht of f a e c e s , a p p r o x i m a t e l y 5 tintes h i q h e r

t h i n l e v e l s found i n t h e p r e s e n t s t n d y . Neither Blood aor I

fauad l ungwora l a r v a e in lamb f a e c e s d u r i n q ~ p r i l , ! l a y , and J u n e ,

Blood (1963) found t h e first lunquorat l a rvae i n l a ~ b faeces i n

J u l ~ , s o a e 6 - 8 r e e k s a f t e r t h e peak of t h e b i r t h i n q p e r i o d .

The absence o f ear l ier s i q n s of lunqwor@ i n f e s t a t i o n s u q q e s t s

t h a t t r a a s p Z a c e n t a l i n f e c t i o n was n o t o c c u r r i n g i n the h e r d a+

that tine f P o r r e s t e r E Senges 3964), Disease s i q n s h a v e n e v e r

b e e n r e p o r t e d frcm t h e h e r d (Blood t 9 6 3 b ) . I o b s e r v e d n o

c o u q h i n q or l a s s i t u d e d v r i n q t h e w i n t e r s o f 1976/77, 1977/78, or

19'7?3/80 a l t houqh Blood f l363Bf o b s e r v e & couqhinq dlurinq t h e

w i n t e r of 9960/61,

P a r a l y s i s t i c k s (Deraacen toy andess,o_n&) were frequent1 p

fonnd on ~ y body from e a r l y F e b r u a r y u a t i l e a r l y Bay i n a l l

y e a r s i n which I was work inq a t t h e s t u d y site, No t i c k s %ere

found o n ewe * Z a ,

Blac k-billed maqp ie s (Pica pica) were r e q u l z t r i l y observed

p e c k i n q a n d p r e s u a a b f y f e e d i n q upon e x o p a r a s i t e s on the 'backs,

necks, and h e a d s of t h e s h e e p (Blood 1963b, Rantsa y 7976b), The

s h e e p t o l e r a t e d a n d e v e n facilitated t h i s b e h a v i o u r by s t o p p i n s

f e e d i a q a n d r a i s i n g t h e head when a magpie would a f i q h t , The

i n c i d e n c e of maqpie - s h e e p i n t e r a c t i o n s declined ~ h a r p l y a•’ t e z

B a y , Uhether t h i s was d u e t o a r e d u c t i o n i n a v a i l a b l e

e x o ~ a r a s i t e s , t o a raoverttent of raaqpies fro@ the s-tudy site, or

to s o a e other factor i s unknown.

Preqnancy d e t e c t i o n a n d e a r l y lawb ~ o r t a l i t y

In a p r e l i m i n a r y s t u a y I found t h a t I could c o n s i s t e a t l y

identify a s a a l l n u ~ b e r o f ewes but was u n a b l e t o i n d i v i d u a l l y

i d e n t i f y t h e a a j o r i t y of a n i m a l s , Those s h e e p I c o u l d identify

s h o v e d broken or d i s t i n c t i v e f y s h a p e d horns, c h a r a c i e r i s t i c

pelaqe p a t t e r n s , or wore c o l l a s s f s o n a n earlier r e s e a r c h

project, R i t h o u t t h e a b i l i t y t o i d e n t i f y i a d i v i d n a l ewes with

lambs, e a r x y p o s t - n a t a l ~ o r t a l i t y c o u l d e a s i l y qa unobsexrred.

The p r e l i ~ i n a r y s t u d y i n d i c a t e d t h a t no r e l i a b l e Beans of

de%esntinimq p r e q n a n q from f i e l d o b s e r v a t i o n s was possible, Tbe

d e q r e e of a o u l t of -the p e l a g e was s u q g e s t e d (D, S h a c k l e t o n ,

p e r s , co@m,) b u t was fonnd n o t to be c o n s i s t e n t w i t h

o b s e r v a t i o n s , f r e q u e n t l y , e v e s d i s p l a y i n q d e l a y e d c o a t moul t

were seen w i t h o u t f o l l o w i n q l a a b s , No ewes showing e a r l y c o a t

~ o u l t were s e e n P e a d i n q l a ~ b s , This might s u q q e s t t h a t e a r l y

pos t - r aa t a l mortal. i t y o f l a a b s was o c c u r r i n g , but w i t h o u t f urthsr

e v i d e n c e i t seemed i n a p p r o p r i a t e to u t i l i z e coat moul t a s a n

i n d i c a t i o n of preqnanc y.

I n 1976 two c o l l a r e d ewes were o b s e r v e d p r i o r t o t h e

l ambinq p e r i o d n e a r t h e cliffs and b o t h were t h o u s h t t o ke

p r e q n a n t due t o t h e i r s w o l l e n abdomens. Both were s u b s e q u e n t l y

o b s e r v e d wi th Panbs, o n e five d a y s and t h e o t h e r seven d a y s

l a t e r , I n t h e i n t e r v e n i n q p e r i o d l d e s p i t e i n t e o s i v e daily

s e a r c h i n g , these ewes were not o b s e r v e d , B o t h ewes were seen

w i t h s u c k l i n q laabs i n late J u n e of t h a t yea r ,

I n 1978 f i v e ewes s u c k l i n q l imbs were i d e n t i f i a b l e , None of

these ewes was o b s e r v e d t o h a v e l o s t a lastb d u r i n q the

o b s e r v a t i d n p e r i o d , I n 9956 s i x ewes w i t h l a ~ b s #ere

identifiable and, of t h e s e , one a p p a r e n t l y l o s t h e r l a a b b y

early Ju ly .

It is known t h a t b i q h o r n s once i n h a b i t e d t h e lower valley

bot tola qrass lands in the S i a i l k a ~ e e n V a l l e y u n t i l recent times

fBlood l % l ) , It is tezupt inq t o s p e c u l a ~ e t h a t t w i n n i n q miqht

h a v e bee^ s e l e c t e d f o r i n t h e lusher and c l i m a t i c a l l y less

r i q o r o u s i n t e r i o r B r i t i s h C o f u ~ b i a valley bot tom nhereas it may

be less a d a p t i v e i n the p r e s e n t l y a v a i l a b l e s h e e p r anqe , F o r

ewes c a p t u r e d on t h e Yaseifux r ange , 12.5% of t h e e v e s obsez'sed

(n = 36) qave b i r t h t o t w i n s { W c l e s F Shack le ton 7 9 7 3 ) . I f a

s i&iPar t w i n n i n q r a t e was o c c u r r i n g i n the Ashnola h e r d s and i f

t w i n s had a s i g n i f i c a n t l y lower p r o b a b i l i t y o f s u r v i , v a l , u n d e r

p r e s e n t c o n d i t i o n s t h e n t h i s c o n l d have a n i m p a c t upon the

observed l a ~ b : e u e rat ios .

, IB 1978 a t o t a l of 5 erses were identifiable, One ewe

w i t h o u t f o l l o v i n q laab was identifiable, None of t h e eves were

observed to have l o s t a Lamb durinq t h e o b s e r v a t i o n a l p e r i o d ,

Three of t h e f i v e 1 378 l a c t a t i n g females were observed in 1979

with laabs, The other 2 ewes w i t h lambs i n 1978 were n o t

i d e n t i f i e d i n 1973, The s i n q l e i d e n t i f i a b l e eve without lamb in

1978 was also without Zaeb i n 1979. In 1980 o n l y 1 of t h e

i d e n t i f i a b l e ewes with laab i n 3878 and 1379 was o b s e r v e d and

she was without a l a ~ b ,

Although the sa~lple s ize is too small to make a definitive

s t a t e n e n t , t h e r e would appear to be some e v i d e n c e t h a t ewes can

breed every year within the popula t ion ,

V, Discussion and C o n c l u s i o n s

Due to t h e l a c k of captures of b i q h o r n sheep the o r i q i n a l

o b j e c t i v e s of t h i s study c o u l d n o t be met, As a r e s u l t the

causes of Che r e l a t i v e 1 y low l ambinq sates o b s e r v e d i n the

f l a t i r o n herd is st i l l not d e t e r m i n e d , However, a s a result of

t h e f e e d i n q m n i p u l a t i o n s c a r r i e d out over t h e 3 w i n t e r s of this

s t u d y it i s p o s s i b l e t o infer some r e l a t i o n s h i p s b e t s e e n

n u t f i t i v e s t a t u s and r e p r o d u c t i v e pe r fo rmance in t h i s h e r d ,

The f e e d i n q , dfuq treatment, and r a n q e bnrninq proqraais

were followed by a s i q n i f i c a n t A n c r e a s e i n the lalnb:eve r a t i o s

i n early snnaer and i n l a g b s u r v i v a l t o year 1, Because tbese

l a a n i p u l a t i o n s were a p p l i e d s i l a u l t a n e o u s l y it i s i n p o s s i b l e to

precisely detersine t h e relative iittpostance of each factcr ,

C o n s i d e r a t i o n of the d a t a fro& ~y own and previous studies does

p e s ~ i l t an e v a l u a t i o n of those factors which were most l i k e l y t o

h a v e c a u s e d the o b s e r v e d a l t e r a t i o n s i n t h e p o p u l a t i o n ,

It would a p p e a r t h a t the T h i a b e n d i z o l e t r e a t i t t e n t h a s had a n

effect upon lungwom i n f e s t a t i o n i n t h e herd by l o w e r i n s both

t h e s e v e r it y and incidence of occurance. f n f e c t i o n still occurs

w i t h i n t h e populat ion after druq treatment as la~bs born in

7978, af ter the f irst year of #inter f e e d i n q , showed l e v e l s of

i n f e s t a t i o n as y s a r l i n q s which uese coniparab3.e to those of a d u l t

ewes, Druq t r e a t m e n t kt ith T f i i a b e n d i z o l e s u p p r e s s e s l a r v a l output

but d o e s n o t e r a d i c a t e t h e lunqworm fHib le r gl, 1976) . Upon

c e s s a t i o n o f kreatrttent. lungworm i n c i d e n c e w i l l , p resumably ,

r e v e r t back t o p r e v i o u s levels ( H i b l e r eJ 1977, B. Samuals,

B s n o t e d i n t h e i n t r o d u c t i o n , lunqwsrin i n f e s t a t i o n can b e

a s s o c i a t e d with h i q h levels of m o r t a l i t y i n b i g h o r n lambs,

However i n c i d e n c e of Imnqworte i n f e c t i o n , w i t h i n t h e s t u d y

p o p u l a t i o n , p r i o r t a t r e a t a e n t was low r e l a t i v e t o s o ~ e o t h e r

p o p u l a t i o n s o f b i g h o r n s (a/ 1400 lasvae/qltt f a e c e s - S t e l f o x

1976, 566 l a r v a e / q a f a e c e s - Thorne e& sf. 1979, 820 l a rvae /qm

faeces - Uhazy & 22. 19731, Perhaps sos t s i g n i f i c a n t l y , t h e

p a t t e r n of lanrb ~ o r t a l i t y i s n o t t h a t which would be e x p e c t e d i f

tho 1unquor~:pneumnia couxplex gas a major m o r t a l i t y f a c t o r

w i t h i n t h e h e r d (Wooaard g& a&. 1972) I n t h e years p r i o r t o

d r u q t r e a t a e n t 1ainb:eve r a t i o s were r e l a t i v e l y iov from the time

of l aabdnq w h i l e laab s u r v i v a l t o y e a s l i n q status was r e l a t i v e l y

hiqh [Table 3). tosses of larnbs through t h e summer and o v e r

winter were n e v e r >50X a n d f r e q u e n t l y C30% Woodard 2s a, (1974) cite l a a b s u r v i v a l t o autumn, i n a herd i n which

lunqworm: pneuaon ia was a major m r t a l i t y f a c t o r , a s r a n q i n q

between f 3 a n d 23X,

ah tkouqh Blood 11961) o b s e r v e d some couqh inq b y s h e e p i n

t h e ,win te r , no couqh inq was o b s e r v e d i n lambs d u r i n q s u m m r , Yet

summer c o u q h i n q by lambs is a f r e q u e n t l y obse fved s i q n in

p o p u l a t i o n s e x p e r i e n c i n q lunqworm associated mostalf ty (Spraker

G B i b l e r 1977) ,

bunqwora bnrdens c a n a f f e c t a p r e q n a n t eveSs p h y s i c a l

c o n d i t i o n t o t h e e x t e n t that l a ~ b b i r t h s e i q h t s , and hence

p r o b a b i l i t y of s u r v i v a l , can be a f f e c t e d , However qiven t h e

u b i q u i t y of lungworm i n c i d e n c e i n bighorn populations a n d t h e

10% l e v e l s a t which they are f o u n d i n t h e Ashnula p o p u l a t i o n

t h i s would n o t be e x p e c t e d t o be a ~ a j o r e l e m e n t d e t e r m i n i n q a

ewe's physical c o n d i t i o n ,

The low d e q r e e o f u t i l i z a t i o n of t h e recently b u r n e d s l o p e s

by S h e b i q h o r n s uould i n d i c a t e t h a t s u c h areas p l a y an

i n s i g n i f i c a n t role i n t h e n u t r i t i o n a l i n t a k e o f the a n i m a l s on

the w i n t e r ranqe, A d m i t t e d l y n o a n a l y s i s of n u t r i t i o n a l q u a 1 i t y

of burned r a n g e forage was c a r r i e d o u t , however Stoddaf t gs a, 11975) i n d i c a t e t h a t c h a n q e i n foraqe q u a l i t y of g r a s s l a n d s

after b u s n i n q is usnally miniaal,

The l e v e l s of aaamalian p r e d a t i o n appear t o be q u i t e low,

Althauqh eagles were present every year there was n o i n d i c a t i o n

of chanqes i n nnabess from previous y e a r s n o r between years of

t h i s study, This f a c t o r c a n n o t b e c o m p l e t e l y e l i m i n a t e d but it

seem unlikely t h a t e a q l e p r e d a t i o n on l a m b s would be reduced

for t h e 3 s p e c i f i c years o f t h i s s t u d y .

It is n o t e w o r t h y t h a t althouqh t h e r e was s o n e v a r i a t i o n i n

uin%es s e v e r i t y f o r b o t h s u p p l e ~ e n t e d a n d unsupplemented y e a r s ,

the m i l d e s t r e c o r d e d winter i n which t h e s h e e p were not f e d

(1970) was a s s o c i a t e d with a stzbsequent lower larnb:eve ratio

than f o f l o w i n q t h e h a r s h e s t r e c o r d e d w i n t e r o f t h e f e d y e a r s

[1480) , It would a p p e a r that, within the ranqe of w i n t e r s

experienced over t h e p e r i o d 1970 - 1980, s e v e r i t y h a s had f ittfe

effect upon lamb p r o d u c t i o n ,

This is perhaps n o t v e r y s u r p r i s i n g , The severity of

w i n t e r s e x p e r i e n c e d b y b i g h o r n s i n the Ashnola w a t e r s h e d is

r e l a t i v e l y ~ i l d compared t o those experienced b y o t h e r b i q h o r n

p o p u l a t i o n s i n t h e northern os more a l p i n e p o r t i o n s of their

p o p u l a t i o n s e x p e r i e n c i n q harsher w i n t e r s , climatic effects upon

r e p r o d u c t i o n are not p a r t i c u f arlp e v i d e n t , chappe l and Hudson

f t978) have shown tha t : t h e t h e r m o n e u t r a l zone of a b i q h o r n s h e e p

i n v i n t e s c a n ire a s low as -20 C, a t e m p e r a t u r e I r a r e l y

e x p e r i e n c e d on t h e A s h n o l a winter range , S i a i l a r l y t h e r a i n

shadow e f f e c t of t h e C a s c a d e Bountains [Harper 1969) results i n

lower snow fall i n t h e Ashnala reqion t h a n an many other b i q h o r n

raa qes,

I t is r e c o q n i z e d t h a t t h e index of w i n t e r s e v e r i t y utilized

here i s , at best, an approxie r ta t ioa of the a c t u a l s e v e r i t y of

w i n t e r s e x p e r i e n c e d by t h e s h e e p p o p u l a t i o n . Ifowe ver X consider

t h e a s s u t t t p t i o n s aade t o be r e a s o a a b l e assessments of w i n t e r

h a r s h a e s s as r e c o r d e d b y f i e l d o b s e r v e r s 4% i i ebs t er ,

u n p u b l i s h e d f i e l d notes, ay own o b s e r v a t i o n s ) .

The r e l a t i o n s h i p between winter supplemental f e e d i n q and

subsequent laab production is n o t completely obvious. The

a n o m l o u s year of supplemmtal winter f e e d i n q would appear to b e

?979/80 in which more f e e d was p a t out than i n either of t h e 2

p r e v i o u s p e a r s and y e 2 t h e l a x h e w e ratio of sprinq 1980 was

lower than either 4978 or 1979. However i n 1 9 7 9 J B O f e e d was not

a v a i l a b l e d u s i n q the f inal . t h i r d of q e s t a t i o n , Coop and Clark

81969) and Brarnley g& ~1 (1976) report for domestic s h e e p t h a t

the n u t r i t i o n a L p l a n e of t h e ewe durinq the first t /3 Lo 1/2 of

qestation h a s l ittle effect upon birth weight of lambs.

Biqhorn sheep i n captivity and kept upon ad &&&ii~ hiqh

q u a l i t y f e e d diets will v o l u n t a r i l y restrict intake in winter

and lose body weiqht {A, H o t t r e l l , pers, coim,), A b i g h o r n l a e b

kept in c a p t i v i t y a t U.B,C, was observed t o show no h e a l i n s of a

bone, broken in February 1370, until A p r i l of that year i H S

Barnsay, piers. o b s , ) . Hoen (1973) repasts s e v e r a l cases of

vo l untary feed redaction dur inq w i n t e r of a number of u n q v l a t e

species, The metabolic rate of biqhorns h a s been shown to

d e c l i n e throngh w i n t e f and t h e n S o i n c r e a s e aarkedly in spring,

shov ing a d i s t i n c t s e a s o n a l v a r i a t i o n (Chappel E Hudsoo 1978) .

11 is p o s s i b l e t h a t s o m wild ungulates, i n w in ter , are n o t a b l e

to deposit body r e s e r v e s , Hence o n l y imaaediate e e t a b o l i c demands

c a n be &at f r o a n u t r i t i o n a l intake, If t h i s h y p o t h e s i s i s

correct then winter supp lemen ta l f e e d i n q l a t e i n qestation when

f o e t a l deraands a r e hiqh (approximately 30 - 85% of basal. p r o t e i n

requireaents (Moen 1973) ) Bay h a v e a q r e a t e r e f f e c t upon lamb

b i r t h w e i q h t than would winter s u p p l e m e n t a l f e e d i n g e a r l i e r i n

q e s t a t i o n , Altihouqh s p e c u l a t i v e , this s u q q e s t i o n h a s c l e a r

m a n a q e r i a l a p p l i c a t i o n s i f a d e c i s i o n t o w in t e r feed a wild

population is made, F u r t h e r s t u d y m u l d seem u a r r e n t e d ,

Domestic l a a b s h e a v i e r at b i r t h t e n d t o maintain t h e i r

w e i g h t d i s c r e p e n c y t h r o u g h o u t their first year of life (Eqan 22

&, 1977). Consequently heavier laabs at bir th w i l l tend t o h a v e

a greater p r o b a b i l i t y o f s u r v i v a l t h r o u q h t h e i r f i rst winter,

due to a qreater body s ize , than w i l l lambs born a t a l i q h t e r

w e i q h t , Pi l a m b s bosn a f t e r a w i n t e r of s u p p f e a e n t a l f e e d i n q

weiqh h e a v i e r a t birth t h a n those bosn a f tes winters w i t h o u t

supp leaen . t a1 f e e d i n q t h e n this could be a c o n t r i b u t o r y f a c t o r i n

t h e i n c r e a s e d Ian& s u r v i o a l to a q e 1 i n the yeass 1977 - 1380,

T h e a v a i l a b i l i t y of s u p p l e ~ e n t a l fee& d u r i n q a l a @ b i s first

winter would be e x p e c t e d t o h a v e a s p a r i n q effect upon body

r e s e r v e s , This too woald t e n d t o promote latnb s u r v i v a l ,

The Zarqe drop i n t h e lambtewe r a t i o s sirare t h e early

? 3 6 0 * s w a r r e n t s f u r t h e r i n v e s t i q a t i o n . Perhaps a study d i r e c t e d

t o the r a n q e i s a q a i n in o r d e r so t h a t c c t m p a s i t i v e v a l u e s before

and a f t e r cattle r e a o v a l would be available, The degree a•’

i a p t o v e a e n t o f t h e % i n t e r ranges s i n c e c a t t l e removal would be

of interest, Q u a l i t a t i v e l y t h e sanqes a r e i n a q r e a t l y improved

c o n d i t i o n , y e t t h e p o p u l a t i o n size h a s c o n t i n u e d t o a e c r e a s e ,

The guestion of w i n t e r f e e d i n q itself i s one which ~ i q h t be

addressed . General concensus amnq manaqers i n North Bmerica

seems to be that winter: feedknq i s a l a s t resort seasure (Ramsay

& Seip 1979) . If s u b s e q u e n t s t u d i e s show t h a t laab production i s

r e l a t e d to t h e degree of w i n t e r feei i inq then a c t i o n can be taken

to correct the liaitinq f a c t o r , However if f a e d i n q is t o

c o n t i n u e a s a technique for i n c r e a s i n q lamb p r o d u c t i o n and not

as a tool. f o r ineest iqat ing the factors lintitinq the populat io ; l

then t h e population may be i n a precarkous p o s i t i o n , Cessation

of winter f e e d i n g a f t e r s e v e r a l years could result i a a

p o p u l a t i o n d e c l i n e ,

I conclude t h a t o v e r w i n t e r n u t r i t i o n had t h e qreatest

effect upon the reproductire performince of the herd, The

condition of the f e ~ a l e i n l a t e preqnacy i s known to b e

i~portant to n e o n a t e s u v i v a l i n many species of unqulates, The

l aan ipu la t ions of the s n p p l e n e n t a l winter f e e d i n q proqram

c o i n c i d e d with t h e o b s e r v e d lamb produc t ion i n a way t h a t

appeared consistent vith the oversinter n u t r i t i o n model.

FhXs is somewhat s u r p r i s i n q a s t h e removal of cattle i n

1968 resulted i n an immediate i ~ p r o v e m n t i n ranqe conditions

[ S c h e f f l e r 1973) and presu~ably an increase in t h e ove,rwinter

n u t r i t i o n a l p lane of t h e sheep . Y e t lamb p r o d u c t i o n has r e m a i n e d

low since t h a t t h e ,

Recoa mendations

d *

A s t u d y of ranqe c o n d i t i o n s be conducted t o a s c e r t a i n the

d e g r e e of i ~ p r o o e m e n t of the r a n g e s s i n c e cat t le r e a o v a l ,

2. Yearly counts of t h e herd s h o u l d be c o n t i n u e d i n order to

a o n i t o r any chanqes in popula t ion characteristics, These

should be made i n e a r l y spr inq , p r i o r t o lainbinq i n crdes to

ensure ra@ c o u n t s and a q a i n i n June when most l ambs have

been born and b e f o r e t h e s h e e p have qone t o t h e i r summer

ranqes, Counts should b e conducted i n a s tandard ized manner

and a t t h e sawe t i a e of year o n each o c c a s i o n ,

3, The winter f e e d program be stopped for I or 2 y e a r s , w h i l e

t h e a n t 5 - h e l n i n t h i c druq and burninq proqrams be continued,

and t h e p o p u l a t i o a moni tored , The h y p o t h e s i s would be t h a t

the larlab:ewe r a t i o s uould be reduced i n y e a r s f o l l o w i n q no

winter f eedinq.

tC, If w i n t e r supplementary feedinq is t o be c o n t i n u e d t h e n it

s h o u l d be a p p l i e d during the l a t t e r part of q e s t a t i o i .

Idea l ly , the feedinq proqraa c o u l d b e used a s a too l to

i n v e s t i g a t e t h e reproductive performance of the herd.

Appendix I

Composition of Buckerfields sheep pellets (#3270)

Protein (N x 6.25)

Fat (ether extract)

Fibre (crude)

Salt

Calcium

Phosphorus

Vitamin A

Vitamin D 2

Vitamin E

Copper

Manganese

Zinc

Iron

Cobalt

Iodine

Seliniun

Detection of pregaancg in l i v i n g biqhorn sheep by p r o q e s t i n

determinat ion

p u b l i s h e d in The Journal of W i l d l i f e fianaqeimnt (1979) Val. 43:

970-973,

D e t e r n i n a t i o n of pregnancy rates i n w i l d unqulate

populations u s u a l l y has required the death of the i n d i v i d u a l s

s a r p l e d . C r e w sea Hawkins (1967) and F o l l i s and Spillet (1978)

d e t e r a i n e d pregnancy i n the l i v e elk (Cervus s&s&gi_s&) by

rectal p a l p a t i o n of ovaries - studies that appear to be unique, Preqnancy rate d-e tern ina t ions are often required froin

populations that ntap b e too sgtal.1 t o allow for s a a p l i n q o n l y

d e a d a n f a a l s . Por e x a e i p l e , many b iqhorn sheep {Wis ~ m ~ e n s i s f

herds are s m a l l , stable, and k - s e l e c t e d { G e i s t 1975). fn

s o u t h - c e n t r a l British Colambia, repeated low lambinq crops (20 - 30 laabs/100 ewes) i n t h e sntalf herds of C a l i f o r n i a b iqhorns @;

s&Agorniam) have prompted an i n v e s t i q a t i o n of preqnanc y

rates i n p o p u l a t i o n s where sampl inq dead sheep is inopportune,

~ e s i p h e r a l g l a s ~ a proqesterane Pevef s i n doitiestic ewes have

been found t o be an accurate indication of greqnancy. Dur inq t h e

final half of g e s t a t i o n , proqesterone levels a r e c o n s i s t e n t f y

h i q b e r than i n cycling or a a o s t r u s ewes IBassett and T h o r b u r n

1973). Siai l irr patterns have been found i n b iqhorn s h e e p b y E,H.

BcEvan and P,E, V h i t e h e a d (personal caamanica t ion) , Ve attempted

to determine the accuracy of pseqnancp d i a q n o s i s froa asfays of

t o t a l proqes$iras i n a s i n q l e blood saaple t a k e n dorinq the

l a t t e s ha l f 05 q e s t a t i o n from captive and wild b i g h o r n eues.

Three Rocky Elountain eves (& canadensi_s) sere

maintained i n c a p t i v i t y a t t h e U n i v e r s i t y of British Colu~bia by

the Canadian Wildlife S e r v i c e , Durinq the latter 2/3 o f

pregnancy, f s o ~ F e b r u a r y t o Bay 1977, %hay were repeated1 y

s a a p l e d u n d e r r e s t r a i n t , Single s a ~ p l e s uese also t a k e n f r o a 2

of these eves i n O c t o b e r f 976, prior t o their j o i n i n q w i t h rams,

S i n q l e blood s a a p l e s , t a k e n under restraint, were obtained f r o @

4 a d d i t h n a l graups: (1) 2 Bock7 Mounta in ewes ( D e p a r t m e n t of

Aniaal. Science, U n i v e r s i t y of A l b e r t a ) ; /2) Y Rocky Ploun ta in

ewes (Depa r tmen t of Zoofogy , U n i v e r s i t y of B r i t i s h C o l u a k i a ] ;

13) 14 C a l i f o r n i a e v e s fOLanaqan Gaae Parts, P e n t i c t o n , BIG. ) ;

and (4) 20 C a l i f o r n i a ewes on their d a y of c a p t u r e f rom t h e

Vaseaux Lake h e r d i n southern B r i t i s h C o l u a b i a , T e n sf the

c a p t u r e d ewes froat t h e Vaseaux Lake herd were t a q q e d a n d m v e d

t o the Okanaqan Gaae Far& Soee of these ewes were s u b s e q u e n t l y

resaapled after b e i n q i n c a p t i v i t y for 1 year,

Blood was taken froa t h e jugular vein, Plasma samples were

c o l l e c t e d in heparinkzed V a c u t a i n e r s ( s e c t o n , D i c k i n s o n G Co, ,

t l i s s i s s a u g a , O n t a r i o ) , c e n t r i f u g e d w i t h i n 4 h o u r s of collection,

and f r o z e n a t -20 C until a n a l y s i s ,

ae initially a n a l y z e d our s a ~ p f e s for t o t a l p s o q e s t i n

l e v e l s by Beans of a c o ~ m e r c i a l l g a v a i l a b l e r a d l o i m u n o a e s a y kit

( B i o k i t p r o q e s t e r o n e , B i o l a b S, A,, Brussels, BePqiuaf . Sarapies

were s u n i n d u p l i c a t e without a n extraction step, I n t 978 we

c h a n g e d t o a different comntercial. k i t (Progesterone

R a d i o i a m u n ~ a s s a y P a k , New Eaqland N u c l e a r , Qorcester,

P lassachuse t t s s ) that i n c l u d e d a n e x l s a c t i o n s t e p u s i a q reaqent

q r a d e p e t r o l e u a t ether, S a m p l e s a s s a y e d w i t h o u t an e x t r a c t i o n

s t e p show q e n e r a l l y h i q h c r p r o q r s t i n l e v e l s than assays w i t h a n

e x t r a c t i o n s t e p . However i n the case of p r eqnancy d i a g n o s i s ,

p r e c i s i ~ n a n d s p e c i f i c i t y of d e t e r m i n a t i o n of c i r c u l a t i n q

hor inones i s of less interest t h a n the qeneral d i f f e r e n t i a t i o n of

the h i g h proqes terone l e v e l s o f preqnancy from t h e low

proqesterone l e v e l s of n o n p r e g n a n t a n e s t r u s animals {Suqden

3978)e

On 4 o c c a s i o n s samples of b o t h plasm and serulzt were t a k e n

s i m u l t a n e o u s l y , Little d i f f e r e n c e i n p r o q e s t i n c o n c e n t r a t i o n ,

d e t e r a i n e d w i t h o u t e x t r a c t i o n , between plasm a n d serum was

found, Plas ina c o n c e n t r a t i o n s were 1083, 33.2, l l , 4 , and 3,7

nq('w1 cotapared with seruba c o n c e a t r a t i o n s of 9.8, 10,6, 11.9, and

8 , 3 ng/oal, r e s p e c t i v e l y .

The p l a s ~ a p r o q e s t i a l e v e l s of the 3 serialfv sawpled

Canadian V i l d l i f e Service's ewes a r e shown i n P i q , 1 , Ewes P-3

a n d F-2 laabed on 20 a n d 21 Hay, r e s p e c t i v e l y , Ewe B-36 d i d n o t

produce a laoab, The f l u c t u a t i o n s i n v a l u e s f o r t h e 3 ewes, up to

5 Bay, are sisilas to those r e p o r t e d , b o t h between i n d i v i d u a l s

and o n a daily basis, f o r d o r a e s t i c eves d u r i n g t h e latter 2/3 of

gestation (Bassett et a l e 1969, G l e e s o n and Thorburn 797Q) . Both

eues that lambed shored l e v e l s of <0.5 nqdmh a t 9 and 10 d a y s

p o s t p a r t u ~ , This is similar t o postpartup levels Ear d o m e s t i c

sheep @tabtteafdd-t et a l e 3972). Two of t h e ewer; (El-15 and P-21

h a d been sampled 3 weeks psiar t o j o i n i n g with raas a n d then had

p r o q e s t i n l e v e l s of 0.6 a n d 0.1 aq /wl , r e s p e c t i v e l y . With the

TOTAL PROGESTIN CONCENTRATION (nglml)

e x c e p t i o n of ewe 3- I6 after 5 Play, the l e v e l s of p s o q e s t i n s i n

b o t h n o n b r e e d i n q a n d p r e q n a n t ewes are i n a g r e e m e n t w i t h t h e

r e p o r t e d v a l u e s f o r d o m e s t i c s h e e p ( S t a b e n f e l d t et a l , 1963,

Thosburn et a l e 1959, Y u t h a s a t r a k o s o l et a l . 19751 ,

Following t h e f i n a l s a m p l i n g o f b l o o d from ewe B-36 on 2 5

June 1977, t h i s aa i l ga l was moved frona U,B,C, and n o further

e x a m i n a t i o n was p o s s i b l e , However, t h e p a t t e r n of low proqestin

l e v e l p r i o r t o j o i n i n q by rams f o l l o w e d by a steady rise i n

p r o q e s t i n c o n c e n t r a t i o n f rom February to e a r l y May i n d i c a t e s

t h a t t h i s ewe was p r e g n a n t , The s u b s e q u e n t d e c l i n e i n l e v e l s

t h r o u q h l a t e J u n e aay i n d i c a t e that r e s o r p t i o n of the fetus was

o c c u r r i n q ,

P r o g e s t e r o n e concentrations of 2.44 nq/@2 [Gadsby et a l ,

1972) and 1,48 nq/ml. fUeiql et al, 1975) h a v e b e e n p roposed a s

t h r e s h o l d l e v e l s fo r determining preqnancy i n d o m e s t i c eues, Our

d a t a suqqest t h a t a plasrna p r o q e s t i n v a l u e be tween 2 a n d 3 nq/af

d u r i n g t h e latter 2/3 of q e s t a t i o n c o u l d be used as a t h r e s h o l d

for p r e q n a n c y d i a q n o s i s i n b i q h o r n sheep,

Table 1 shows the mean proqestin l e v e l s of the s i n g l y

s amp led ewes a n d t h e r e l a t i o n s h i p b e t ween p reqnancy d % a q n o s i s

{i, e, , p r o q e s t i n s >2.5 n q / a l ) and subsequent l a a b i n q ,

Twen ty - f ive d i a q n o s e s of p regnancy proved correct a s d i d 13

d i a q a o s e s of nonpreqnancy. Bhen t h e d a t e o f b i r t h of a l a ~ b was

know, t h e a p p r o x i m a t e s t a q e of qestatioxl o f t h e ewe on the

s a a p l i n q d a t e was est imtea, b a s e d upon a q e s t a t i o n l e n q t h of

8 9

Table 1.

Progestin levels, pregnancy diagnosis, and subsequent lambing results in bighorn sheep.

Assay kit, source of

Ewes

Progestin

Pregnancy

Day of

* Ewes lambing

ewes, sampling date

(N)

(ns/ml) diagnosis

gestation

(N)

Biolab S.A.

Vaseaux Lake

16 Mar 1977

10

9.8-20+

POS .

136-153

10

Okanagan G.P.

2

1.4, 1.8

Neg .

11 Apr 1977

Univ. Alberta

2 May 1977

New England Nuclear

Okanagan G.F.

15 Mar 1978

Univ. B.C.

21 Feb 1978

Vaseaux Lake

26 Mar 1978

1

20+

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5

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7

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2

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2

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0.5

Neg .

* Calculated from birth date of lambs.

** Estimated from date of earliest sighting of all lambs born.

175 d a y s [ B l u n t et al, f 3 7 7 ) .

The p lasma p z o q e s t i n levels o f t h e 1977 Vaseaux Lake

s a m p l i n g and of the U n i v e r s i t y of A l b e r t a ' s ewes were qeaerally

much hiqher than those of t h e o t h e r s ample s . T h e 1978 Okanaqar,

Game Farlrt s a a p l e s i n c l n d e d raany of the sarrte animals saatpled t h e

y e a r p r e v i o u s l y a t Vaseaux Lake, and t h e y 4i.d n o t show elevated

levels such as they had i n 1377. The 1978 traseaux Lake s a m p l i n q ,

as sell, d i d n o t show s u c h e l e v a t e d p r o q e s t i n levels,

D e s p i t e d i f f e r e n c e s i n ~axiaum levels o f plasma p r o q e s t i n s

between different g r o u p s of b i q h o r n ewes, it is clear t h a t the

r a d i o i a m u n o a s s a y of b l o o d p r o q e s t i n s from a sinqle sample

p s o v i d e s a u s e f u l d i a q n o s t i c tool t o de t e r i i t i ne prsqnancy rates

in w i l d b i q h o r n s h e e p p o p u l a t i o n s . The t e c h n i q u e itself is

relatively s i tnp le , i n e x p e n s i v e , and r a p i d .

Acknow 2edqn&_nQ. - We t h a n k E.B, BcEWaE for t h e o p p a r t u n i t y

So silrtlple -the Canadian O i l d l i f e S e r v i c e t s h e r d a n d f o r r e v i e w i n q

an e a r l y draf t of t h e m a n u s c r i p t , and H.C. Mordan for t h e

o p p o r t u n i t y t o sarsple t h e U n i v e r s i t y of British Columbia h e r d ,

D, E~ils ley a n d A. Botrell a ided in c o l l e c t i n g sas lp les . and D,

Seip assisted i n assay d e t e r ~ i n a t i o n s , Plasma s a m p l e s were

r e c e i v e d f ro@ R.J. Hudson, E, Lacey, and R, Peterso-n. D.S,

Eastmiin and 1. R o b e r t s o n q a v e &uch s u p p o r t arid i n f o r m a t i o n , This

r e s e a r c h was supported b y Eunds E s o ~ a P ~ e s i d e n t ' s R e s e a r c h

Graq t , S i m n F r a s e s U n i v e r s i t y , a n d a n o p e r a t i n g qrant from the

B r i t i s h C o l u a b i a F i s h and f k l d l i f e Branch.

LITERATURE C f T E O (Appeedix IIj

Bassett, 3,14,, T , J , Oxborrow, X . D , Smi th , and G,D, T h o r b u r o . 1 969, The c o n c e n t r a t i o n of p r o q e s t e r o n e i n the p e r i p h e r d p l a s a a of t h e p r e g n a n t ewe, J, E n d o c r i n o l . 45: 443-453.

Basset t , J,fi,, and G , D . Thorbu rn , 3973. C i r c u l a t i n q l e v e l s of p r o q e s t e r o n e a n d c o r t i c o s t e r o i d s i n t h e p r e q n a n t ewe a n d its foetus, Pages 126-140 ~JC, G, P i e r r e p o i a t , ed, The e n d o c r i n o l o q p of p r e g n a n c y and p a r t u r i t i o n - e x p e r i m e n t a l studies a n the sheep . h lpha -Q~eqa -Alpha , C a r d i f f .

B l u n t , F , E I , , H, A, Dawson, and E,T, 'Ilhorne, 1977, Birth w e i q h t s a n d g e s t a t i o n i n a captive R w k y 8oun8ain b i q h o r n s h e e p . 3. f i a ~ a a P , 58: 306,

F o l l i s , T,B,, a n d 3, J , S p i l l e t , f 974, @inter preqnancy rates and s u b s e q u e n t fall c o n / c a l f r a t i o s i n e l k . 4. ~ i l d l , Hanaqs, 38 : 789-?P 1

Gadsby, J , E , , R,B, Heap, D.G, P o w e l l , and D.3, @ a l t e r s , 3972, D i a g n o s i s of p r egnancy a n d of t h e number of foetuses i n sheep from plasttla p r o g e s t e r o n e c o n c e n t r a t i o n s , V e t . Rec, 90: 339-342,

G e i s t , V, 1975. Oa t h e aanaqe~ent of mounta in sheep : t h e o r e t i c a l c o n s i d e r a t i o n s , P a q e s 77-98 h a . B, Trefe then , e d , The wi ld s h e e p i a laodern North America, Boone a n d C r o c k e t t Club, New York, 302 pp,

Gleeson, B.R., and G,D, Thorburn , 1974. S e l e c t e d f a c t o r s t h a t a f f e c t the m a s u r e a n t of p l a s a a p r o q e s t e r o n e concentrations i n preqnant enes, Aust , J , ~ i o l , S c i . 23: 658-689,

Greer, K,R,, a n d f , W , Hawkins, Jr, 1967, Determinins preqnanc)! i n e l k b y rectal p a l p a t i o n , J, g i l d l , Manaqe. 3 I : 145-349.

S t a b e n f e l d t , G , H . , J , A , H o l t , and L , L , Ewinq. 1969, p e r i p h e r a l p lasma p r o q e s t e r o n e l e v e l s a u r i n q the o v i n c oestrus cycle. E a d o c r i n o l , 85: 11- 15,

S t a b e n f e l d t , G.H,, M, Drosh, a n d C. E, F r a n t i , 1972, P e r i p h e r a l p lasma p r o q e s t e r o n e levels ia t h e ewe d u f i n q

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LITERATURE CITED

Andersoa, R,C. 1975, R e l m i n t h s , pp, 35-43, in Paqe, L,A, &?a,), g i l d l i f e Diseases, Plenum P r e s s , New YorL 6 8 6 pp,

Anon, 1 W8a, Annual R e p o r t 3 977378. f l i n i s t r y of R e c r e a t i o c and C o n s e r v a t i o n , P r o v i n c e of ~ r i t i s h Cofuab i a . 65 pp.

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B a s t i ~ a n , B, 1972, The effect of ewe c o n d i t i o n a t tuppinq o n lanabinq p e r f o r m a n c e , Expt, Rusb, 22: 22-24,

B e r g e r , 3 , 19?8a, Baternal defensive b e h a v i o r i n b i q h o r n sheep* 3, Hammal, 59: 620-52 1,

Berger, 3 , 1378b. Group size, f o r a g i n q , and a n t i p r e d a t o r p l o y s : a n a n a l y s i s of biqhorn sheep decisions, Behau, Eco l , S o c i o b i o l , 4: 91-99,

Be rqe rud , A,?, 1979, Baalsay, @,A. and D.R, ~ e i p ( e d s , ) , Syspos ium on Voff P r e d a t i o n , Simon F r a s e f Dn iv , , ~ u r n a b y , 103 pp*

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B l u n t , Pel%, H,A, Dawson, a n d E,T, Thorns , 1977, B i r t h w e i q h t s and g e s t a t i o n i n a c a p t i v e Rocky ~ o u n t a i n b i q h o r n s h e e p , J. Plaarrtal, 58: 106,

Bone, J,N, 1969, Some p o p u l a t i o n p a r a m e t e r s 05 the Ashnola herd of C a l i f o r n i a b iqho rn , ELC, Fish and Wildlife Branch. Unpub, R e p o r t , 12 pp,

Braatley, P,S,, Ha&, Denehp, and 3 , E , Meston, 1975, "re ,effect of d i f f e r e n t planes of nutrition before mating on t h e r e p r o d u c t i v e p e r f r o m a n c e of Masham ewes, Yet, Rec, 93: 294- 296,

27, DeForqe, 3 , R . 1976, S t r e s s 2 is it l i m i t i c q h i s h o r n s ? Trans, Des, Biqhosn C o n , 20: 30 3 1.

28. Dena rch i , R.A. 1965. An e c o l o q i c a l study of t h e Ashnola biqfnoxn winter r a n q e s , Unpub l i shed B, Sc, t h e s i s , IJ ,E.C,

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30, Eas tnan , D,S, f 979, Q Raasay , #. A. and D,R. S e i p (eds,) . Symposium on %olf P r e d a t i o n . Simon F r a s e r Univ., Burnaby, 1103 gpm

31 , E c c l e s , T,R, and D m M s S h a c k l e t o n . 1979. R e c e n t r e c o r d s of t w i n n i n g i n Nor th American mounta in s h e e p , J, Wildl . ffanaqe, 43: 874-976,

32, f q a n , J,K., $. L. Thonapson, a n d J , S , McIntyre, 1377, S t o c k i n q rate, j o i n i n g time, f o d d e r c o n s e r v a t i o n a n d t h e p s o d a c t i v i t y of H e r i n o ewes. 2, B i r t h we igh t , s u r v i v a l and qrclvth 0 5 lambs. Aus t . J, Expt , 8gs i c . Bnira, Husb. 17: 909-914,

33. E l l e a b e r q e r , JOB. 1976. The e p i z o o t i o l o q y of p s o - t o s t r o n q p l o s i s ia a Poudre River b i q h o r n sheep h e r d , P s o c , lorth, g i l d Sheep Counci l : 89-94,

34, Ericksan, J,A, 1970, Use of d r o p net and collars i n s t u d y of Dall sheep , P roc , Worth, Wiln S h e e p Coun, : 20-21.

35, F o r r e s t e r , D, J, l 9 7 f , Biqhorn s h e e p lunqwora-pneumonia complex, p p , 158-173. D a v i s , J,%. a n d R , C , Anderson ( e d s , ) , P a r a s i t i c Diseases of P i l d Mammals, Iowa S t a t e Univ, Press. 3 6 4 pp,

36. F o r r e s t e r , D , J , and C, PI, Senge r , 1954. Prenatal infection of b i q h o r n s h e e p w i t h P r o t o s t r o n q y l i d lunqworms, N a t u r e 201: t053m

37. Franznaann, All#, 1972, Envi ronlaenta f s o u r c e s o f , v a r i a t i o n o f b i q h o r n sheep p h y s i o l o q i c values, 3 , W i l d l , Hanaqe. 36: 924-932,

38, F r a n c i s , P.J, 1973. Accuracy o f census methods of terr i tor ial r e d winqed b l a c k b i r d s . 3. W i i d l , Elanaqe, 37: 98-102. 657: 6Q7-650,

39, G a t e s , C,C, and He@. Samuel, 1977, P r e n a t a l i n f e c t i o n of

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P e r i p h e r a l t h e r m o r e q u l a t i o n : foot t e m p e r a t u r e i n two ~ r c t i c c a n i n e s , S c i e n c e 175: 988-990,

52, H i b l e r , C , ? . , R O E , Zanqe, a n d C.Jb fietzqer. 1972, T r a n s p l a c e n t a f t r ans&iss ion of P r o t o ~ t r ~ n ~ l ~ ~ spp , i n b i q h m n s h e e p , 3 , f i l d l , D i s , 8: 389,

53, RiMer, C . P . , T,R. S p r a k e r , a n d R 8 L * S c h ~ i d t , 1376. T r e a t s e n t of b i q h o r n s h e e p f o r funqrorm, Trans, I, Amer, Wild S h e e p Conf, 2: 66-68,

54, Hibler , C , P , , T,B, Spsaker, a n d R.L, S c h e i d t , 1977, Trea t l t l en t of bighorn s h e e p for lunquorm, T rans , Desert Biqhorn Coun, : 32-1 4,

55, Horejsi, B, 1975, Soae t h o u g h t s a n d o b s e r v a t i o n s o n h a r r a s s m e n t a n d b i g h o r n sheep , P r o c , North. Wild Sheep CQ~D,: 149-155.

56. Bornocke r , R, 1959, D e f e n s i v e b e h a v i o r i n f e m a l e b i q h o r n sheep, 3, Naetmal, 50: 128,

57, Hudsan, R , J , 1972, S t r e s s - i n d u c e d immunoloqic impa iraent in Rocky Houn ta in bighorn s h e e p , P r o c , Nor th , g i l d Sheep Coun, Syap,: 31-3Y,

58, Kelsall, J,p , 1368, The e i q r a t o r y b a r r e n - q r o u n d c a r i b o u of Canada* Can, B i l d l , S e r v , Bonoqr, 3: 1-340,

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6 0 , Kis tner , T,P, and D. Ygse, 1973, T r a n s p l a c e n t a l t s a n s ~ i s s i o n o f Protostpmqyf9s s p , i n ~ a l i f o r n i a biqhorn sheep f 0 v i s c a a a a e n s i s c a l i f o r n i a u ) i n Oreqon. J , ~ ~ i f d l . P i s , 15: 551-562,

61, Kniqht, A,P, 1980. Xy laz ine , J, Baez. B e t , Ned, Assoc, 176: 456-455,

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63 , Lentz, C,P, and J ,S, Hart, 1960, T h e e f f e c t of wind and w o i s t u r e on heat l o s s t h r o u q h t h e f u r of newborn caribou,

. Can, J. Zool, 38: 679-688,

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