Murder and Deceit: How One Bird Gets a Meal

If birds could read, this tale of deceit and murder would shock the avian world.

A parasitic bird called the Horsfield's hawk-cuckoo lays an egg in the nest of another bird species, such as the bushrobin. That's just the beginning of the treachery. When the hawk-cuckoo chick is born, it pushes the bushrobin's natural offspring out of the nest.

Trickery


A hawk-cuckoo chick displays the tricky wing pattern ...


... tricking the surrogate mother into feeding it.

Images courtesy journal Science



In a different strategy, an invading cowbird (larger, left) joins its nestmates at the dinner table.

Mark Hauber/UC Berkeley

And the newborn hawk-cuckoo has another trick up its sleeve or, rather, up its wing feathers.

Scientists have wondered how the parasitic chick gets fed, because other studies have shown that it takes the stimulation of multiple open beaks -- either the sight or the sound -- to compel a mother bushrobin to provide food.

The clue to the mystery is in bright yellow patches on the ends of the hawk-cuckoo's wings.

Japanese researchers found that the chicks make those patches quiver, and they mimic the mouths of other chicks. So the lone nestling gets fed.

The patches don't resemble open mouths all that much, the scientists say, but it seems the bushrobins can't tell the difference in a relatively dark nest. The researchers tested the idea by covering the yellow patches with black paint. When they did that, the parasitic chicks got less food.

The study was done by Keita Tanaka and Keisuke Ueda of Rikkyo University in Tokyo and is detailed in the April 29 issue of the journal Science.

The hawk-cuckoo isn't the only parasitic bird. America's brown-headed cowbird is also a nest invader. But the cowbird joins its nestmates in a chirping chorus to bring in more food than it could on its own, according to a separate study announced last year.

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