Mere fear shrinks bird families | Science News


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Mere fear shrinks bird families

Just hearing recordings of predators caused sparrows to raise fewer babies

2:03pm, December 8, 2011

Nothing but fear itself can actually be dangerous for nesting birds.

Song sparrows protected from attack but subjected to recordings of predator yowls and leaf-crunching approach noises raised 40 percent fewer offspring in a year compared with neighbors living amid innocuous noises, says population ecologist Liana Zanette of the University of Western Ontario in Canada. Predators do not need to kill a single prey to have a big effect, she says.

Scary noises, broadcast where the sparrows nested in the wild, took a toll throughout the breeding season, Zanette and her colleagues report in the Dec. 9 Science. The alarmed sparrows laid fewer eggs to begin with, and they proved such

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