Response of eastern chipmunks to conspecific alarm calls

Abstract

Eastern chipmunks, Tamias striatus, were more likely to flee the area and assume a motionless alert posture in response to playback of conspecific alarm calls than they were in response to two types of control (silence and white-noise). Qualitatively similar responses were given to three call types: trills (single calls typically given as chipmunks evade a pursuer), chucks (repeated calls typically given by motionless animals after detecting an aerial predator), and chips (repeated calls typically given by motionless animals after detecting a terrestrial predator). However, chipmunks showed a higher probability of fleeing and slightly longer alert times in response to chucks than to chips. Chipmunks did not differ in their response to calls recorded from different individuals or calls played back at different amplitudes, but calls played at higher rates, and from two speakers as opposed to one, elicited longer alert responses. Visual and auditory disturbances during playback of chips and chucks resulted in a higher probability of fleeing and longer alert times than did the same disturbances in the absence of calls. These results suggest that chipmunks are sensitive to characteristics of alarm calls that could indicate a degree of risk, and that part of the response to these calls is an increased awareness of visual and auditory stimuli associated with the approach of a predator. © 1995.