Airdate: Mar 21, 2001
Scientist: Kevin J. McGowan, PhD
CROWS: Uncommonly Cooperative
Come nesting season, families of crows do something relatively few other species of birds do - raise their young cooperatively.
The common crow. To native Americans he was the keeper of sacred law and an omen of change. For ornithologists, crows do something which not many other species of birds do - they raise their young cooperatively. I'm Jim Metzner, and this is the Pulse of the Planet. This month marks the start of the breeding season for crows.
American crows do things a little bit differently in the breeding season than do most birds in North America."
Professor Kevin McGowan is associate curator of birds and mammals at Cornell
University in Ithaca N.Y.
"When you go to watch a nest you'll see more than just two birds attending the nest. I've even had occasions where I have seen about ten individuals that are coming to the nest and feeding young. This phenomenon of having many individuals feeding young in a nest, more than just the parents, is unusual in this part of the world and is known as cooperative breeding..."
Instead of leaving the nest, some of the older brothers and sisters of this years nestlings stay around to help their parents
"Helpers help in a number of ways. They do essentially everything that the parents do except lay the eggs. They defend the territory They will, to a limited extent, help build the nest. They will help feed the female while she's incubating the eggs. She's the only one who's allowed to actually warm the eggs. But once those eggs hatch, then the helpers will help feed those nestlings. Once the young come out of the nest, they're moving around, they still need to be fed for a long period of time after that, and the helpers take an active role in that as well."
This year's nestlings become helpers the following spring. The oldest helpers eventually move on to find mates and raise their own families. Like us, these common crows live in a world of family and shared responsibility. Altogether - they’re a rather uncommon bird.
Pulse of the Planet is presented by the National Science Foundation.