Detecting Migratory Waves of Tree Bats Using Acoustic Methods
Advisor Information
Jeremy White
Location
UNO Criss Library, Room 249
Presentation Type
Oral Presentation
Start Date
4-3-2016 10:45 AM
End Date
4-3-2016 11:00 AM
Abstract
Previous studies using acoustics to identify bats during their migratory periods fail to identify the acoustic patterns of “migratory waves,” defined as large concentrations of bats moving through an area during migration. The purpose of this study was to determine a system for recognizing migratory waves of Lasiurus cinereus (hoary bat), Lasiurus borealis (eastern red bat), and Lasionycteris noctivigans (silver-haired bat) by identifying specific call characteristics—i.e. duration, time, and type of call—that differ from calls during the resident period (June 15-30). We used two acoustic analysis programs to classify bat calls collected over two years (March 2013-December 2014) by an ultrasonic detector at Camp Catron and Retreat Center in Otoe County. We reported the presence of a species when both programs agreed on the identification of that call. Our results show large peaks in hoary bat calls in July. Analysis of these calls showed significant differences in call characteristics compared to calls identified during the resident period. We compared these results to Eptesicus fuscus, a known resident species, which saw little to no difference in call characteristics between peak nights and the resident period. Analysis of eastern red bat calls showed no significant difference between characteristics of their peak nights and the resident period. The silver-haired bat calls showed slight differences between peak nights and the resident period; however further research is required to determine the significance of these variations. These results indicate that comparing these call characteristics may be helpful in identifying migratory waves of hoary bats.
Detecting Migratory Waves of Tree Bats Using Acoustic Methods
UNO Criss Library, Room 249
Previous studies using acoustics to identify bats during their migratory periods fail to identify the acoustic patterns of “migratory waves,” defined as large concentrations of bats moving through an area during migration. The purpose of this study was to determine a system for recognizing migratory waves of Lasiurus cinereus (hoary bat), Lasiurus borealis (eastern red bat), and Lasionycteris noctivigans (silver-haired bat) by identifying specific call characteristics—i.e. duration, time, and type of call—that differ from calls during the resident period (June 15-30). We used two acoustic analysis programs to classify bat calls collected over two years (March 2013-December 2014) by an ultrasonic detector at Camp Catron and Retreat Center in Otoe County. We reported the presence of a species when both programs agreed on the identification of that call. Our results show large peaks in hoary bat calls in July. Analysis of these calls showed significant differences in call characteristics compared to calls identified during the resident period. We compared these results to Eptesicus fuscus, a known resident species, which saw little to no difference in call characteristics between peak nights and the resident period. Analysis of eastern red bat calls showed no significant difference between characteristics of their peak nights and the resident period. The silver-haired bat calls showed slight differences between peak nights and the resident period; however further research is required to determine the significance of these variations. These results indicate that comparing these call characteristics may be helpful in identifying migratory waves of hoary bats.