Door County Avian Waste Survey

and Bird Count

Colleen McDermott, D.V.M., Ph.D.University of Wisconsin Oshkosh

Oshkosh, WI 54901Phone: (920) 424-1102FAX: (920) 424-1101

Mcdermot@uwosh.edu

Sources of E. coli at Recreational

Beaches• Human waste• Agricultural runoff• Domestic pets• Avian waste

– Gulls– Ducks– Geese– Others

Door County

• While all sources are possible, avian waste has been suggested as important source

• Large numbers of gulls and geese at some beaches– E.g. Whitefish Dunes & gulls– E.g. Otumba Park & Geese

Avian Waste

• Contains:– 3.7 X 108 fecal coliforms/gram feces (Alderisio &

DeLuca, 1999)– E. coli (indicator organism of fecal contamination)

-Potential pathogens• Salmonella• Campylobacter

– Avian waste as source of E. coli may have lower potential to cause disease in humans than other sources

Ways to ID Source of Contamination

• Many have been suggested– DNA fingerprinting (E. coli & other fecal organisms)– Antibiotic Sensitivity Profiles– Caffeine concentrations– Etc.

• None are easy or definitive• Often bird counts at beaches have been used to

determine impact of avians on beach health– Once/day snapshot count– Longer term counts

Other Ideas?

• Quantify amount of avian waste on beaches, rather than bird numbers

• Summer 2004– Counted and classified avian waste “droppings”– 10 Beaches in Door County– Each beach was counted 1X/week for 14

weeks– Used random grid counting method

Method

• Sampler throws square grid (1.5 m2) in transect zone along swash zone

• Counts waste within grid and classifies type of bird waste

• Moves to next location 45.5 m along swash zone

• Throws grid again and counts• Repeats for a total of 9 sampling plots

Figure 1: Sampling scheme for avian waste enumeration (Fish Creek, WI)

40

14

23

5

149

12

57

10

21

97

0

20

40

60

80

100

120

Avi

an W

aste

Cou

nt/b

each

/day

13 15

27

5 7 4 5

26

410

90

0

10

20

30

40

50

60

70

80

90

100

Baileys H

arbor

Egg Harb

or

Ellison Bay

Ephriam

Fish C

reek

Newport

Otumba

Portage

Sister

Bay

Sunset

White

fish D

unes

Bir

ds/b

each

/day

Table 1: Pearson Correlations for Avian Waste and Bird Counts with E. coli

Beach

Avian Waste vs.

Bird Counts

Avian Waste vs.

Bird Counts: p-value

Avian Waste vs.

E.coli

Avian Waste vs. E.coli : p-

value

Bird Count vs.

E.coli

Bird Count vs.

E.coli: p-value

Baileys Harbor 0.138 0.745 -0.365 0.374 -0.434 0.282Egg Harbor -0.191 0.574 0.521 0.100 -0.149 0.662Ellison Bay 0.063 0.871 0.043 0.913 0.880 0.002Ephraim 0.563 0.090 -0.135 0.711 -0.117 0.748Fish Creek 0.000 1.000 -0.216 0.524 -0.057 0.868Newport 0.853 0.003 -0.166 0.670 -0.036 0.927Otumba 0.229 0.474 -0.184 0.567 0.695 0.012Sister Bay 0.103 0.778 -0.008 0.982 0.478 0.162Sunset -0.255 0.424 0.505 0.094 -0.045 0.891Whitefish Dunes 0.129 0.397 -0.172 0.259 0.345 0.020

Table 1: Proportions of bird types in Door County, WI Summer 2004

Beach Gulls as percent of total birds present

Geese as percent of total birds present

Mean log10 E. coli concentration

Baileys Harbor 78% 21% 1.44

Egg Harbor 53% 43% 1.45

Ellison Bay 41% 27% 1.65

Ephraim 61% 27% 1.05

Fish Creek 36% 30% 1.58

Newport 88% 4% 0.79

Otumba 18% 73% 1.68

Sister Bay 67% 7% 1.30

Sunset 78% 18% 1.79

Whitefish Dunes 100% 0% 1.17

Summary

• Avian waste counts do not correlate with bird numbers nor with E. coli concentration in beach water

• At a few beaches bird counts do correlate with E. coli concentrations in beach water

• Proportions of gulls vs. geese does not seem to affect E. coli concentrations in beach water

Future Work

• In Summer 2005 we will expand project– Count avian waste and bird numbers at 13

beaches in Door County– Add numbers to ensure our statistics are

powerful– Continue to collect avian waste samples for E.

coli isolations, DNA fingerprinting, antibiotics sensitivity profiles

Thank you

Questions?