- Litvais, John A.
University of Maine Graduate School
Bobcat (Felis rufus) prey use, habitat use, and home range size were compared to the distribution and density of snowshoe hare (Lepus americanus) in 2 study areas in Maine. The habitat variables that influences hare habitat use and density were identified within each study area. These variables were then sampled within the home ranges of transmitter-equipped bobcats to examine the relationships among bobcat habitat use and home range size, and hare abundance.
In Cherryfield, hare preferred hardwood and avoided mixed wood and open understories (p<0.05). Hare use of understories increased as hardwood stem density increased (r=.36, p<0.0001). In Pierce Pond, hare used softwood more, and hardwood and open understories less than expected (p<0.05). Hare pellet density was strongly associated with softwood stem density in this area (r=.52, p<0.0001). Although differences in understory cover and composition existed between areas, snowshoe hare responded similarly to relative differences in understory cover within each area.
Snowshoe hare remains were observed in over 60% of the bobcat feces collected during all seasons in both study areas. Other prey included white-tailed deer (Odocoileus virginianus), moose (Alces alces), Small mammals, muskrats (Ondatra zibethicus), porcupines (Erethizon dorsatum), and birds. Prey ramains in 230 bobcat carcasses indicated that prey use varied with bobcat age, sex, and weight.
Thirty bobcats were captured, marked, and released. Twenty one individuals were monitored for .>3 months. Resident adult males occupied ranges (x=95.7 km2) approximately 3 times as large as adult females (x=29.8 km2) and yearling females (x=35.5 km2). Male female bobcats occupied the largest portion of their total home ranges (>50%) during the gestation season (16 Mar-15 May) and smallest portion (<20%) during the nursing (16 May-15 Jun).
Over 6,000 habitat samples were collapsed were collected along 400 KM of transects within bobcat home ranges. Use availability analysis revealed several bobcat habitat home ranges. Use availability analysis revealed several bobcat habitat prefernces. In Cherryfield, bobcats preferred hardwood understories, while in Pierce Pond, softwood understories were used more than expected (p<0.05). These pattern corresponded to the habitat preferences of snowshoe hare in both areas. Bobcats also avoided open understories and steep slopes, possibly because these areas contained few hare.
resident bobcat home range size was compared to bobcat age, weight, and index of winter severity, estimated hare density, and other habitat variables within home ranges. When all bobcats were combined into a single multiple regression model, bobcat weight explained 45% of the variation in home range size (p<0.0002). The combination of weight and the amount of edge within a home range accounted for over 60% of the variation of home range size. Therefore, hare density was a poor indicator of bobcat home range size in the 2 study areas.