Vol. 44, No. 1
David M. Larson
Black-capped Chickadee. Photograph by Peter Oehlkers.
For tasty morsels like songbirds, being aware of the surroundings and alert to the dangers of predators is a critical skill set. Membership in a mixed feeding flock can be advantageous, since different species with diverse viewpoints can help the group detect danger and sound the alarm. Behavioral, visual, and auditory clues all can help with predator avoidance. Many species respond stereotypically to visual cues of different predators; for instance, Red-winged Blackbirds mount a more vigorous response to a Red-tailed Hawk than to an American Kestrel.
But what about using auditory clues from the predator? Birders know well that vocalizations of potential predators can attract prey species. Presumably knowing the exact location of that screech owl—or the human mimic—provides a level of certainty and safety. The response of birds can often be scolding and mobbing, so keeping the predator in sight and alerting and attracting conspecifics and other species to the threat seems a good defense mechanism.
Do birds react differently to the vocalizations of potential predators and the specific threats they pose? Billings et al. (2015) conducted a series of audio playback and recording experiments in Montana and Washington in winter on mixed flocks containing three species of chickadees: Black-capped (Poecile atricapillus), Mountain (P. gambeli), and Chestnut-backed (P. rufescens). They played vocalizations of three predators: Northern Pygmy-Owl (Glaucidium gnoma), Sharp-shinned Hawk (Accipiter striatus), and Northern Goshawk (Accipiter gentilis) and one nonpredator control, Townsend’s Solitaire (Myadestes townsendi) and recorded the vocal responses from the chickadees.