Birds may have more complex brains than previously thought. Birds apparently scope out ever better breeding grounds and then remember how to get back to them after spending winter half a world away, researchers say. What factors make wild birds choose specific places to nest? Conservationists would like to know in order to setup protected habitats that will attract bird populations.

In Sweden scientists noticed that collared flycatchers would peer into various nests about the neighborhood. One spring the scientists kidnapped some newly hatched flycatcher chicks and placed them in nests at another site to be raised by foster parents. The scientists then monitored an area with overcrowded nests, an area with under populated nests and two untouched control spots.

The following spring, the flycatchers migrated back from a winter in Africa to choose their nesting sites.

The flycatchers that had their young abducted from the crowded neighborhood the previous spring, moved to another spot to build their nest. The parent birds had spent less time hunting food the previous summer, due to lack of mouths to feed, and had spent more time scoping out future nesting sites.

They had apparently judged their past neighborhood and other crowded neighborhood as poor rookeries and set up house in a less crowded area. Birds new to the area settled in the overcrowded area, probably figuring that they could successfully raise their young in an area where many chicks were already present.

“Potential immigrants probably have to rely on less information to choose where to go” than the locals do, Zoologist Blandine Doligez, now with the University of Bern.

Curiously enough, the flycatchers whose nests were crowded by the addition of the abducted chicks also moved their nests. The birds that cared for the unexpected adoptions found it difficult to feed the extra mouths, so the chicks weren’t as healthy as those in less crowded nests, according Doligez.

“It’s a very creative and impressive study,” Russell Greenberg, director of the Smithsonian Institution’s Migratory Bird Center mentioned.

French scientists are ready to report similar results from a study of kittiwakes, Doligez claims, which suggests that checking out better neighborhoods may be common among various bird species. Conservationists will use the results of the study to develop a more sophisticated method of determine how birds view potential habitats.

“It’s not just sufficient to count birds anymore,” Greenberg quoted. “It’s more important to know what the birds value in terms of where they’re willing to settle; and their ability to produce healthy, viable and many young to carry on the gene pool is a critical thing.”

Greenberg remains intrigued by a bird’s cognitive abilities. That a bird can look for a new neighborhood one summer and remember that spot until they return the next summer from half way around the world is remarkable, he claims.

The study flies in the face of long held beliefs that birds are programmed to use a general nesting area. “We’re seeing a switch now to the actual cognitive-based decision-making
birds gather information and they make decisions,” Greenberg said. The Swedish study “opens up all kinds of questions about the mechanisms of how they do it,” he added.

Tag: Birds use Complex Thinking to Decide Where to Live