Assessing Mammalian Habitat Use on the Boston Harbor Islands
Delivered at the 2011 Boston Harbor Islands Science Symposium
In the summer of 2011, we initiated a pilot study to evaluate the utility of rangers and island visitors in providing baseline observational data of the mammals on the Boston Harbor Islands. Based upon those findings, it is apparent that many medium to large species of mammal utilize the islands intermittently. In contrast, small mammal species are assumed to be permanent residents of the islands on which they are found. A multiyear study designed to assess small mammal populations and habitat use on one of the islands (Bumpkin) revealed a major reduction in Microtus populations and demographic changes in the Peromyscus population. This population crash and concurrent demographic alteration may have been due to changes in resource availability or to the sporadic presence of medium to large mammalian predators on the island.