Description of Spring Roost Trees Used by Female Indiana Bats (Myotis sodalis) in the Lake Champlain Valley of Vermont and New York

Abstract

Extensive effort has been directed at the roosting ecology of the federally endangered Indiana bat (Myotis sodalis) during the maternity season; however, spring roosting ecology has received much less attention. In April 2002, radio transmitters were attached to the back of 19 female Indiana bats as they emerged from a hibernaculum in northeastern New York. Thirty-nine roost trees were found in the vicinity of the Lake Champlain Valley of New York and Vermont over the span of 224 bat days (i.e., 1 bat located for 1 d equals 1 bat day). Distances from hibernaculum to roost trees ranged from 14.6 to 40.0 km (mean = 26.9 km). Shagbark hickory (Carya ovata) was the most common (33.3% of all trees, 39.7% of all bat days) of 11 tree species used. Roost trees had a mean diameter of 45.6 cm, were 18.9 m tall and were similar in structure to those used during summer by Indiana bats elsewhere in their range. This study provides the first large-scale examination of trees used by female Indiana bats after spring emergence, supplying critical life history information useful for the conservation of this species.