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Individual variation in the dear enemy phenomenon via territorial vocalizations in red squirrels

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Title: Individual variation in the dear enemy phenomenon via territorial vocalizations in red squirrels
Author: Robertson, Jack G
Department: Department of Integrative Biology
Program: Integrative Biology
Advisor: McAdam, Andrew
Abstract: Territoriality arises when the benefits of exclusive access to resources exceed the costs of defense. Behavioural plasticity increases the net benefits of territoriality by reducing defensive effort, often through the dear enemy phenomenon where familiarity reduces intrusion risk. Red squirrels (Tamiasciurus hudsonicus) follow the dear enemy phenomenon, but the mechanism by which red squirrels recognize conspecifics is unknown. I hypothesized that they use territorial calls, and predicted that familiar calls would better deter intruders than unfamiliar calls. I temporarily removed squirrels from their territories and replaced them with a speaker broadcasting the owner’s call, an unfamiliar call, or silence. Owner calls did not more effectively repel intruders than unfamiliar calls. However, intruder identity varied: unfamiliar neighbours intruded during owner playback, but familiarity did not affect intrusions during unfamiliar playback. Individual variation in familiarity and changes in population density and composition can affect the strength and detectability of dear enemy effects.
Date: 2018-09
Rights: Attribution-NonCommercial-NoDerivs 2.5 Canada
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Attribution-NonCommercial-NoDerivs 2.5 Canada Except where otherwise noted, this item's license is described as Attribution-NonCommercial-NoDerivs 2.5 Canada