Date of Award

Spring 5-1-2003

Document Type

Thesis

Degree Name

Master of Arts (MA)

Department

Life Sciences

First Advisor

John O. Whitaker Jr.

Second Advisor

Greg Bierly

Third Advisor

Steven L. Lima

Abstract

Temperate insectivorous bats have historically used such structures as hollow trees, slabs of loose bark, foliage, and caves as roosts. With the advent of modern man in North America, human-built structures have become available to bats. Eptesicus fuscus is one of only two species of bats in the eastern United States that regularly utilize human structures as roosts, and the only one that regularly hibernates there. Individual ~- fuscus utilizing the attic of a church on the campus of St. Mary-of-the-Woods College (SMWC) were implanted with passive integrated transponder (PIT) tags. The electronic tag reader was placed near the only exit to the roost, allowing records to be kept of every movement of marked bats both into and out of the roost. Sixty marked bats occurred regularly at SMWC during the hibernation season ("residents during hibernation"). Fiftyone marked bats occurred regularly in summer ("summer residents"). Most bats that hibernate at SMWC do not spend their summers there, and vice versa. Of the 20 bats that iv occurred regularly in both ("permanent residents"), the majority was male. Sex ratio determination was problematic due to seasonal differences in tagging regime, but appear to be male-biased during hibernation and in spring, and femalebiased in summer and fall. Excursions (events during which the animal left and returned to the roost in the same night) during the hibernation season averaged 44.8 min in duration, while movements (events during which the animal left and returned on different nights) averaged 5.8 days. Mass changes over excursions averaged +0.54 g, which is attributed to drinking to offset high rates of evaporative water loss during torpor at high temperatures (10-15 2 C). Mass change over movements averaged -0.243 g. Forearm length was not significantly correlated with number of excursions. "Feeding buzzes" were observed inside SMWC during the hibernation season, but no feeding was evident. Copulations were also witnessed in the hibernaculum, as late as 24 February.

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