Spatial Use and Survival of Sympatric Populations of New England and Eastern Cottontails in Connecticut

The New England cottontail (NEC) Sylvilagus transitionalis is strongly associated with shrubland and early successional habitat and is the only cottontail native to the U.S. Northeast. The distribution and abundance of young forest habitat and NEC populations have declined. The eastern cottontail (EC) Sylvilagus floridanus was introduced into the U.S. Northeast in the early 1900s and uses similar habitat as NEC, but is expanding in distribution and abundance. Little information exists on spatial use, survival, and competition in sympatric populations of NEC and EC. Understanding differences in population demographics may identify important factors or relationships influencing population trends and aid in developing effective management strategies. Our objectives were to quantify home range and core area sizes, annual survival rates, minimum population densities, and range overlap for sympatric populations of NEC and EC at four sites in Connecticut. We monitored spatial use and survival rates of 107 radio-collared rabbits over a 10-y period. Mean annual home ranges and core areas were 10.9 and 2.5 ha for NEC and 5.6 and 1.6 ha for EC. Overlap in home range and core areas was greater within species than between species (NEC-EC). For both species and sex, home range size expanded from winter to breeding seasons. Survival rates were greater for NEC than for EC at all four sites, with predation as the major cause of mortality for both species. Space-use patterns suggest that the potential for EC to interfere with NEC reproduction is limited and avoidance or resource partitioning between species in the same patch may be occurring.