138 Cathryn H. Greenberg and Michael R. Pelton 



ranges shared by adult male-female pairs and subadults suggested 

 that family units are spatially segregated. However, this conclusion 

 is tentative because uncollared foxes may have lived undetected 

 within the study area. Trapp and Hallberg (1975) suggest that a 

 family shares a home range exclusive of others, and they provide 

 some evidence for territoriality. 



We were unable to detect any influence of seasonal dietary 

 composition or dietary trophic level on home-range size. Instead, we 

 suggest that diverse, interspersed habitat types within home ranges 

 might provide sufficient food supply in all seasons. Maintaining a 

 home range encompassing sufficient habitat area and types to provide 

 a year-round food supply might be a better strategy than shifting 

 home-range size in response to fluctuating patch productivity or 

 food availability (MacDonald 1980). Further study, including a larger 

 sample size, is warranted to determine the influence of seasonal diet 

 on gray fox home-range size. 



Trends in home-range size indicate that males may range farther 

 than females during breeding season. High variance and small sample 

 size may obscure detection of seasonal differences in patterns of 

 home-range size or differences among age groups or sexes. 



Predominantly nocturnal activity has been reported in other 

 studies (Nicholson 1982). Lower levels of sunrise activity during 

 flesh diet season, breeding season, and months of low foliar cover 

 could all be a response to sparse cover (November-April). Energy 

 conservation during a period of lower food availability may be a 

 factor. Higher daylight activity during pup-rearing season than during 

 other seasons might be due to increased energy requirements for 

 both parents and pups. 



ACKNOWLEDGMENTS— This research was funded by the 

 Oak Ridge National Laboratory, Oak Ridge, Tennessee, operated by 

 the Martin-Marietta Energy Systems, Incorporated, for the U.S. 

 Department of Energy, under contract DE-AC05-840R2 1400. We wish 

 to thank P. D. Parr for her invaluable logistic support and assistance. 

 Thanks to H. A. Longmire, W. Sera J. Gittleman, A. Echternacht, 

 B. Dearden, T. Fendley, J. Evans, M. O'Neil, R. Sargeant, M. Sargeant, 

 and S. H. Crownover for advice and assistance. 



