Bobcat Habitat Use and Home Range Size in Relation to Prey Density

Abstract

Bobcat (Felis rufus) diet, habitat use, and home range size were studied in relation to snowshoe hare (Lepus americanus) density and distribution in 2 areas in Maine during 1979-84. Hare remains occurred in 63-76% of bobcat feces collected during all seasons in both areas. Habitat use patterns of 12 transmitter-equipped bobcats in eastern Maine indicated that they used hardwood understories more, and softwood and mixedwood understories less than expected (P 5* (P < 0.05). The average home range of resident male bobcats (95.7 kmn2) was 3 x as large as that of resident females (31.2 km2) (P < 0.05), and home range size was correlated with bobcat weight (r2 = 0.45, P < 0.002). Metabolic home range size (km2/kg075 body wt) of bobcats was inversely correlated with stem cover unit density and estimated hare density (r2 = 0.22, P < 0.05). Estimated hare density and average topographic slope within bobcat home ranges accounted for 50% of the variation in metabolic home range size (P < 0.006). J. WILDL. MANAGE. 50(1):110-117 Many factors influence vertebrate habitat use and home range size, including energy requirements, prey distribution and density, reproductive requirements, and intraand interspecific relations (Stenger 1958, McNab 1963, Schoener 1968, Smith 1968). Among these, prey density has been reported to be inversely correlated with home range size (Smith 1968, Holmes 1970, Mares et al. 1976). Large variation has been observed in bobcat home range sizes. Bailey (1974) reported bobcats in Idaho occupied ranges from 9 to 108 km , and bobcats in Alabama occupied ranges <4 km2 (Miller 1980). Buie (1980) observed a 4-fold increase in home range size in South Carolina 13 years after Marshall and Jenkins (1967) studied bobcats in the same area. Buie suggested that changes in land-use patterns caused declines in prey populations and resulted in decreased bobcat density and increased home range size. Snowshoe hares are the major prey of bobcats in Maine (May 1981, Major 1983). Therefore, bobcat habitat use within home ranges should be influenced by the distribution of hares. Bobcats occurring in areas with relatively dense hare populations may occupy smaller ranges than bobcat in areas with low hare densities. The objective of our study was to determine the relati nship between bobcat habitat use and home range s ze and snowshoe hare distribution and abundance in Maine. This research was supported by the Maine Coop. Wildl. Res. Unit, U.S. Fish and Wildl. Serv., Maine Dep. Inland Fish. and Wildl., Wildl. Manage. Inst., and the Univ. Maine, cooperating. A. G. Clark, J. H. Hunt, and L. Perry made valuable contributions in executing and funding this study. We thank students at the Coll. For. Resour., Univ. Maine, and Unity Coll. that provided field assistance. We also thank J. W. Ault III; J. R. Gilbert; G. L. Jacobson, Jr.; D. M. Leslie, Jr.; R. B. Owen, Jr.; and R. E. Rolley for reviewing this report. This is contribution 1078 from Maine Agric. Exp. Stn.