Cornell Bird Study

CURRENTS ALOFT

Even casual birders know that some bird species use familial cooperation to raise new broods. Siblings and other relatives regularly provide food for nestlings.

Cornell researchers have, for the first time, linked a specific aspect of the environment to the evolution of cooperative family life in numerous bird species: unpredictable rainfall.

Authors Dustin Rubenstein and Irby Lovette report in the Aug. 21 issue of “Current Biology” that among African starlings, cooperative breeding is most common among species that live in savannas, where the rainfall varies greatly from one year to the next.

“When you don’t know what conditions you will be facing in the next breeding season, it pays – in an evolutionary sense -to live and breed in family groups because more chicks survive over the long haul,” said Rubenstein, the study’s lead author.

Lovette, a program director at Cornell, said, “Birds that breed in groups buffer the effects of an uncertain environment.”

To determine patterns of breeding behaviors of starlings and the environments where they live, the authors examined rainfall pattern records from thousands of African sites recorded for more than a century.

(c) 2007 Intelligencer Journal. Provided by ProQuest Information and Learning. All rights Reserved.