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Songbird Color Vision: Attracting Mates, Avoiding Predators

April 25, 2005

Differences in color vision allow songbirds to be less obvious to predators yet maintain their attractiveness to other songbirds, according to newly released research. In some bird species, males attract mates with bright, elaborate plumage, but such conspicuous traits can draw the attention of predators. Birds can see ultraviolet (UV) light, but mammalian predators cannot, suggesting that UV-reflecting feathers may act as a private communication signal between birds. Such a signal, however, would not protect small birds from larger birds of prey. Previous studies indicate that songbirds, such as sparrows, see shorter UV wavelengths compared with avian predators, such as hawks. To determine if differences in UV perception could influence detection in the wild, Anders Ödeen and colleagues measured UV reflections from the plumage of Swedish songbirds within their natural habitats. Using mathematical models, the authors calculated how songbird plumage would be seen from the perspective of birds of prey versus other songbirds. The researchers found that the songbirds' feathers were more conspicuous to other songbirds than to their avian predators, suggesting the evolution of a private signaling system. These results emphasize the importance of accounting for differently tuned sensory systems when studying animal behavior and evolution.

Abstract © 2005 PNAS

“Differences in color vision makes passerines less conspicuous in the eyes of their predators,” Olle Håstad, Jonas Victorsson, Anders Ödeen, PNAS 04 25 05

Anders Ödeen, Uppsala University, Sweden