Degree Name

Master of Science (MS)

Semester of Degree Completion

1999

Thesis Director

Paul V. Switzer

Abstract

I used playback experiments to test whether alarm calls affected the foraging behavior of Eastern chipmunks (Tamias striatus). I subjected chipmunks, foraging at artificial feeding stations, to three playback treatments (silent, control noise, and alarm call) and examined changes in vigilant and foraging behavior. Chipmunks responded to alarm calls with a greater degree and duration of vigilant behavior, such as look-ups and alert postures. Chipmunks also ran a shorter distance to cover, ran more directly to cover, and took longer to re-emerge from the burrow after hearing an alarm call. Alarm calls caused individuals to spend more time out at the feeding stations, however, these individuals took significantly fewer seeds after hearing an alarm call. This was not due to a difference in the time spent handling food, but rather a slower rate of loading. Chipmunks appear to sacrifice energy gain by increasing vigilance after hearing an alarm call. This study suggests that, to avoid the costs of unnecessary escape behavior, individuals directly assess their own risk rather than relying only on indirect cues such as alarm calls.

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