Context-specific alarm calls of the eastern chipmunk, Tamias striatus

Abstract

The structure and context of alarm calls produced by chipmunks (Tamias striatus) at a field site in southern Quebec were recorded during opportunistic field observations and experimentally simulated hawk attacks. Chipmunks produced three call types in the presence of predators. Chipping consisted of a series of high frequency notes with a rapid downward frequency slope (9.6 to 2.8 kHz) and was given in the presence of mammalian predators by chipmunks perched on a raised vantage point. Chucking consisted of a series of lower frequency notes also sloping downwards (2.5 to 0.4 kHz), given in the presence of avian predators by perched animals. The trill was a lower amplitude, multi-note call usually given only once by animals before reaching a refuge while fleeing from either type of predator. The average trill contained 6–11 downward sloping notes (7.3 to 0.8 kHz). The alarm call types of eastern chipmunks appear to be similar to those reported for western chipmunks. However, they differ in the clear separation of the calls for aerial and terrestrial predators. Chipmunks differ from most other terrestrial sciurids in giving repeated calls for aerial as well as terrestrial predators and in using a call just before reaching a secure refuge.