Exit/entry Sequences, Roost Fidelity, and Transport of Young by Big Brown Bats (Eptesicus fucus) at a Summer Roost

Big Brown Bats (Eptesicus fucus);exit flight;entry flight;roost fideilty;hierarchy;College of Arts and Sciences: Biology

Mayrberger, SheriFlint ;

University of Michigan

关键词: Big Brown Bats (Eptesicus fucus);    exit flight;    entry flight;    roost fideilty;    hierarchy;    College of Arts and Sciences: Biology;   

Others  :  https://deepblue.lib.umich.edu/bitstream/handle/2027.42/117723/Mayrberger.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

I recorded every exit and entry flight of each member of a sizable big brown bat (Eptesicus fuscus) maternity colony using an infra-red camera and VCR at a roost with just a single access/egress hole. I made recordings during 150 consecutive nights in the summer of 2002. Twenty-two bats were fitted with ;;ball-chain;; necklaces bearing unique symbol tags to determine whether maternity colony members exit or the roost in a specific sequence, i.e., exhibit a fixed hierarchy. I reviewed video tapes in slow-motion and recorded flight times to the nearest second, for all marked unmarked individuals. Although, I found no exact flight sequences, exit patterns at sunset and return patterns at sunrise were not random and certain bats occupied specific positions within the sunset emergence and sunrise return flights. The lone adult male in the roost routinely emerged after all other bats before dawn. In gathering sequence data, roost fidelity data were automatically obtained. Overall fidelity of marked individuals varied between 37% and 93% although a few individuals exhibited 100% fidelity during some portion of the reproductive period. Average roost fidelity of marked females decreased from 85%, during early pregnancy, to 62% during late pregnancy, increased to 83% during lactation, and then dropped rapidly to 9% during post-lactation. Fidelity, or lack there of, was affected by females occasionally transporting prevolant offspring to and from alternate roosts. During a three week period, 0.5% of all flights were with attached young. Babies were always transported singly and transport flights only occurred after the sunset foraging bout was completed. Mothers likely transported large babies only when they could not be disengaged from the teat, and occasionally transported large babies that were probably not their own.