Ecology of Red Fox (Vulpes vulpes) in the Lassen Peak Region of California, USA

by

John D. Perrine

Department of Environmental Science, Policy and Management University of California, Berkeley

Fall 2005

Ecology of Red Fox (Vulpes vulpes) in the Lassen Peak Region of California, USA

by

John Dixon Perrine III

B.S. (Vanderbilt University) 1991 M.S. (Miami University) 1995

A dissertation submitted in partial satisfaction of the

requirements for the degree of

Doctor of Philosophy in

Environmental Science, Policy and Management

in the

GRADUATE DIVISION

of the

UNIVERSITY OF CALIFORNIA, BERKELEY

Committee in charge:

Professor Reginald H. Barrett, Chair Professor Stephen R. Beissinger

Professor James L. Patton

Fall 2005

Ecology of Red Fox (Vulpes vulpes) in the Lassen Peak Region of California, USA

© 2005

by

John Dixon Perrine III

Abstract

Ecology of Red Fox (Vulpes vulpes)

in the Lassen Peak Region of California, USA

by

John Dixon Perrine III

Doctor of Philosophy in Environmental Science, Policy and Management

University of California, Berkeley

Professor Reginald H. Barrett, Chair

The red fox population inhabiting California’s Cascade and Sierra Nevada

mountains (Vulpes vulpes necator) is listed as a State Threatened species, but its

management has been hindered by a lack of basic ecological information. I conducted a

comprehensive study of the red foxes in the Lassen Peak region to quantify their local

distribution, resource utilization, activity patterns, niche overlap with likely competitors

and genetic affinity with other red fox populations. The population was restricted to the

region’s highest elevations, occurring >1300 m and primarily within the western half of

Lassen Volcanic National Park. Red fox detections at camera traps in summer were

positively correlated with elevation, highway density and the detection of coyotes, and

were negatively correlated with shrub and herbaceous cover; in winter, detections were

positively correlated with elevation, highway density and mature closed-canopy forest

cover. Their diet was predominantly mammals, especially rodents and mule deer

(Odocoileus hemionus), supplemented by birds, insects and manzanita (Arctostaphylos

nevadensis) berries as seasonally available. Lagomorphs were virtually absent from the

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fox diet. Collared red foxes (n = 5) had large seasonal home ranges (95% MCP; mean =

2,564 ha in summer and 3,255 ha in winter). On average, summer locations were 479 m

higher than winter locations. Their summer range is likely unsuitable in winter due to

deep soft snow and the lack of lagomorphs, a critical winter food for many other red fox

populations, and these factors may limit the Lassen red fox population. Marten (Martes

americana) used the same habitat as the foxes but preyed upon smaller rodents and were

more diurnal. Coyotes (Canis latrans) were nocturnal like the foxes but were generally

at lower elevations and ate larger prey. The Lassen foxes all had the same mtDNA

haplotype, which was the most common haplotype among historic V. v. necator

specimens and was rare in the exotic fox populations from California’s lowlands.

Ecological and genetic evidence indicates that the Lassen red foxes are the native,

threatened V. v. necator, not exotic foxes dispersed from the lowlands. Additional

research is necessary to locate additional mountain red fox populations in California and

to identify the factors preventing their dispersal to the lowlands and vice versa.

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i TABLE OF CONTENTS

Table of Contents..................................................................................................................i List of Tables.......................................................................................................................ii List of Figures.....................................................................................................................iv Acknowledgements.............................................................................................................vi Introduction..........................................................................................................................1 Chapter 1: Seasonal Food Habits of Red Fox, Coyote and Marten in the

Lassen Peak Region of Northern California..................................................15 Chapter 2: Distribution and Habitat Associations of Red Fox, Coyote and Marten

in the Lassen Peak Region as Indicated by Camera Trap Surveys................53 Chapter 3: Activity Patterns of Sympatric Red Fox, Coyote and Marten

in the Lassen Peak Region...........................................................................109 Chapter 4: Home Range and Habitat Use of Radio-Collared

Mountain Red Foxes....................................................................................131 Chapter 5: Red Fox Population Structure in California..................................................166 Conclusions: Niche Overlap Among Red Fox, Coyote and Marten in the

Lassen Region..........................................................................................190

Literature Cited................................................................................................................196 Appendix A: Measurements of Scats of Known Species Identity..................................215 Appendix B: TrailMaster Camera Protocol....................................................................217 Appendix C: Red Fox Locations and Home Ranges by Season.....................................221 Appendix D: Parasites of Lassen Red Fox.....................................................................233 Appendix E: Historical Taxonomy of California’s Mountain Red Foxes......................235

ii LIST OF TABLES

Table 1: Field identity versus cytochrome-b identity of scats..........................................38 Table 2: Seasonal diet composition for Lassen red fox, coyote and marten.....................39 Table 3: Dietary niche overlap between pairs of Lassen carnivores................................42 Table 4: Seasonal dietary overlap among all three carnivores.........................................43 Table 5: Annual camera sampling effort in the Lassen region.........................................89 Table 6: CWHR communities represented in general cover types...................................89 Table 7: Variables used in the grid cell analyses..............................................................90 Table 8: Distribution of camera traps and carnivore detections by

CWHR community type....................................................................................91 Table 9: Detection of red fox and marten at camera traps in varying cover types...........92 Table 10: Detection statistics for each target species.......................................................93 Table 11: Univariate analysis of landscape variables in 2.6 km² cells.............................94 Table 12: Pairwise Pearson correlations among cell-level variables................................97 Table 13: Parameter estimates and odds ratios for terms in the landscape-only

model resulting from the stepwise logistic regression...................................100 Table 14: Comparative fit of models by species and season..........................................101 Table 15: Parameter estimates and odds ratios for the most parsimonious

multivariate models for red fox and coyote...................................................103 Table 16: Pairwise species associations at cameras within grid cells

where both species of the pair were detected.................................................104 Table 17: Number of telemetry fixes and monitoring dates for

radio-collared Lassen red fox.........................................................................123 Table 18: Distribution of seasonal detections of carnivores at

baited camera stations....................................................................................123

iii Table 19: Was the number of detections proportional to the amount

of time in each diel period?............................................................................124 Table 20: Follow-up tests of whether species pairs were similarly

distributed within diel periods.......................................................................125 Table 21: Physical measurements at first capture for Lassen red foxes.........................157 Table 22: Number of locations, by type, for each collared red fox................................158 Table 23: Seasonal locations and home range size per collared red fox........................159 Table 24: Dates for seasonal home ranges......................................................................160 Table 25: Selection of cover types by individual red fox in summer........