Year of Publication

2019

Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation

College

Agriculture, Food and Environment

Department

Animal and Food Sciences

First Advisor

Dr. Michael J. Lacki

Abstract

Migration of animals has been studied for decades and has included everything from large terrestrial and pelagic mammals traveling thousands of kilometers to many types of birds flying through several countries to insects going through multiple life cycles in a single migration. The migration of bats has been studied in broad terms to gather coarse information such as distance traveled, connecting summer and winter habitat, and a general understanding of timing. However, only recently have researchers begun to understand the specifics of bat migration including physiology and fine resolution behavior.

Using nine years of spring migration data collected on VHF radio-tagged federally endangered female Indiana bats (Myotis sodalis), I predicted behavior based on previous migration studies for bats that used various methods such as band recovery data, stable hydrogen isotopes, and automated telemetry. My project used aerial telemetry to collect location points while tracking individual bats throughout the migration. I describe distances traveled, how much time bats spent in migration, traveling and foraging behavior during migration, and how weather affects bat behavior. In addition, this project resulted in the location of 17 previously unknown maternity colonies for the species including the southernmost colony known to date. Next, I used temperature data collected from individual bats along with ambient temperature to determine how air temperature affects specific bat behavior. I calculated air temperature thresholds for use of torpor in Indiana bats and described how air temperature affects transition states between torpor and normothermy. Finally, I determined landscape preferences for migrating bats during travel and foraging. Indiana bats tend to migrate in a direct path from hibernaculum to summer grounds and use the habitat in the proportion that it is available. Although bats used forested cover when possible, they did travel in open areas (e.g., across agricultural fields) when necessary to continue along the intended trajectory.

This data set is the first to track individual nocturnally migrating bats via aerial telemetry for the entirety of the spring migration journey. It provides specific information about how far Indiana bats travel and how long they are migrating across the landscape, illustrates a web of connections between summer and winter habitat, describes the effect of weather on bat behavior, and provides landscape use information that can be useful for land managers and developers.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2019.410

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