J. Keagy et al.; (inset) Wikipedia

IQ test. Male birds had to move away plastic covers before they could remove offending red objects from their bowers.

Brainy Birds Get More Chicks

Nerds of the world, take heart. Brainy male birds have more luck with females than do their less-intelligent counterparts, according to a study of the Australian bowerbird. Researchers claim this is the first study to show a link between smarts and mating success in any species.

It's hard to find a bird with a more complex and energetic courtship behavior than the bowerbird. At breeding season, males build a special platform, or bower, on the forest floor to lure females, and they decorate it with rare objects such as blue feathers and shiny bits of glass. They accompany this with varied vocalizations, hopping, and tail-bobbing.

These behaviors help male bowerbirds attract mates, but are the females also looking for a guy with brains? To find out, researchers at the University of Maryland, College Park, mucked with about 30 bowers they found at Wallaby Creek in Australia. Graduate student Jason Keagy took advantage of males' dislike of having red objects in their bowers (they much prefer blue, apparently because of its rarity in natural settings). In one test, he placed a red plastic battery terminal cover in a bower and covered it with a transparent box that the birds had to tip and drag off; in another, he fixed red tiles in the bowers with screws, forcing the birds to try to cover them up with leaves and twigs. The team then used automated video cameras to monitor the bowers.

The best problem-solvers scored the most copulations, the team reports online this month in the journal Animal Behaviour. In the battery-cover test, for example, some birds took only 20 seconds to remove the object, yet a few couldn't do it at all. Mating success varies widely from bird to bird, with number of copulations per individual during the breeding season ranging from zero to several dozen. Roughly speaking, the most competent birds averaged about twice as many copulations as the slowest problem-solvers, the researchers report.

Keagy says he plans to see if the bowerbirds' renowned ability to mimic the calls of other species correlates with problem-solving abilities and success with the ladies. His ultimate goal is to formulate a measure of general cognitive ability, or "g," in bowerbirds.

Carlos Botero, a behavioral ecologist at the National Evolutionary Synthesis Center in Durham, North Carolina, says that as far as he knows, this is the first experimental demonstration of a link between problem-solving ability and reproductive success. "This is a really nice observation," he says, although "at this point, we don't know why this correlation exists"--that is, whether females really are selecting mates on the basis of intelligence or on something such as a sexy dance that is not related to g.

Posted in Brain & Behavior, Plants & Animals, Environment