Event Title

Bird Chatter as an Indicator of Safety: To What Extent Do Eastern Gray Squirrels Rely on Public Information?

Presenter Information

Marie Lilly, Oberlin CollegeFollow

Location

King Building 343

Document Type

Event

Start Date

4-28-2017 3:00 PM

End Date

4-28-2017 4:20 PM

Abstract

In ecosystems where multiple species share the same predators, it is advantageous for individuals to recognize information about the environment provided by other species. Eastern gray squirrels (Sciurus carolinensis) and other small mammals have been shown to exploit heterospecific alarm calls as indicators of danger. Whether or not small mammals recognize non-alarm auditory cues as signs of safety has yet to be shown. The objective of this study was to test the hypothesis that eavesdroppers such as eastern gray squirrels use bird chatter as a measure of safety. I measured the vigilance behavior of free-ranging squirrels in the presence of playbacks of bird chatter or silence after priming them with a playback recording of a Red-tailed Hawk call. In this study chatter was defined as contact calls from birds that were not under threat. Silence was defined as ambient background noise recorded in the absence of bird calls. Squirrels significantly responded to the hawk call playbacks by increasing the time they spent engaged in vigilance behavior as well as number of times they looked up during otherwise non-vigilance behaviors, indicating that they were primed to be vigilant to the possibility of predators in the area prior to the playbacks of chatter or silence. Following the hawk playback, squirrels engaged in significantly lower levels of vigilance behavior (i.e., standing, freezing, fleeing, looking up) during the chatter treatment than during the silence treatment, suggesting they used the information contained in bird chatter as a cue of safety.

Keywords:

ecology, behavioral ecology, predator-prey interactions, eavesdropping

Notes

Session II, Panel 10 - Natural | Resilience
Moderator: Keith Tarvin, Chair and Professor of Biology

Major

Biology

Advisor(s)

Keith Tarvin, Biology

Project Mentor(s)

Keith Tarvin, Biology

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Apr 28th, 3:00 PM Apr 28th, 4:20 PM

Bird Chatter as an Indicator of Safety: To What Extent Do Eastern Gray Squirrels Rely on Public Information?

King Building 343

In ecosystems where multiple species share the same predators, it is advantageous for individuals to recognize information about the environment provided by other species. Eastern gray squirrels (Sciurus carolinensis) and other small mammals have been shown to exploit heterospecific alarm calls as indicators of danger. Whether or not small mammals recognize non-alarm auditory cues as signs of safety has yet to be shown. The objective of this study was to test the hypothesis that eavesdroppers such as eastern gray squirrels use bird chatter as a measure of safety. I measured the vigilance behavior of free-ranging squirrels in the presence of playbacks of bird chatter or silence after priming them with a playback recording of a Red-tailed Hawk call. In this study chatter was defined as contact calls from birds that were not under threat. Silence was defined as ambient background noise recorded in the absence of bird calls. Squirrels significantly responded to the hawk call playbacks by increasing the time they spent engaged in vigilance behavior as well as number of times they looked up during otherwise non-vigilance behaviors, indicating that they were primed to be vigilant to the possibility of predators in the area prior to the playbacks of chatter or silence. Following the hawk playback, squirrels engaged in significantly lower levels of vigilance behavior (i.e., standing, freezing, fleeing, looking up) during the chatter treatment than during the silence treatment, suggesting they used the information contained in bird chatter as a cue of safety.