Assessing the use of social calls to attract bats to artificial roost sites
Graduation Date
2015
Document Type
Thesis
Program
Other
Program
Thesis (M.S.)--Humboldt State University, Biology, 2015
Committee Chair Name
Joseph M. Szewczak
Committee Chair Affiliation
HSU Faculty or Staff
Keywords
Bats, Humboldt State University -- Theses -- Biology, Behavior, Ecology, Wildlife, Communication
Abstract
Many conservation strategies for bats focus on supporting or enhancing their roosting and foraging needs. With increasing urbanization and loss of natural habitat, many species have adapted to roost in anthropogenic structures, resulting in increased human-wildlife conflict. Bat boxes can provide alternate housing for bats displaced due to exclusions from anthropogenic structures or loss of natural roosts. Researchers and conservationists have begun to investigate the variety of cues bats use to locate and select possible roost locations, such as visual, olfactory or auditory cues. In this study, I describe the call structure of social calls emitted by Yuma myotis (Myotis yumanensis) at roost sites. I investigated if free-ranging Yuma myotis react to social calls of conspecifics and other bat species at roost sites. I also evaluated the effects of age, sex and reproductive status on behavioral responses to social calls. In the summers of 2013 and 2014, I recorded calls from Yuma myotis using bat detectors mounted outside of roost exits. The recorded social calls divided into two distinct types that I could isolate and identify. Type 1 calls consist of a single frequency modulation (FM) syllable, while Type 2 calls consist of a descending FM sweep, finishing on a hook-shaped component. I broadcast social call and echolocation calls of Yuma myotis and Mexican free-tailed bats (Tadarida brasiliensis mexicana) from newly erected artificial roost sites. Bat activity was significantly higher during playbacks of myotis social calls compared to other playback treatments or silent control nights. Additionally, bat activity remained elevated after playback treatments, indicating a latent effect of playbacks at roosting sites. To test individual responses, bats were placed in a field flight tent and exposed to the same broadcast calls used in the field experiment. Individuals in a flight cage displayed no significant response to social calls, regardless of age, sex or reproductive status. This study provides the first description of social calls in a North American myotis species and suggests that understanding the social relationships of bats at roosting and foraging sites may be useful for informing conservation and management decisions.
Recommended Citation
Brokaw, Alyson Frances, "Assessing the use of social calls to attract bats to artificial roost sites" (2015). Cal Poly Humboldt theses and projects. 2071.
https://digitalcommons.humboldt.edu/etd/2071
https://scholarworks.calstate.edu/concern/theses/x633f3483