Growing up without parents makes endangered birds more flexible

This is it, kids: official permission to stop listening to what your parents tell you–but only if you’re a bird. Many animal parents spend time teaching their young about how to find food and avoid danger, and this usually gives a big boost to their offspring. In a Commentary forthcoming in The Condor: Ornithological Applications, however, Vladimir Dinets of Louisiana State University makes the case that when environmental conditions change, relying on their parents’ way of doing things can actually hinder, not help, young cranes.

Only one remaining population of Whooping Cranes is completely descended from wild birds raised by their parents. On both their breeding grounds in Canada and their wintering grounds in Texas, they’re very picky about what habitat they use, sticking to a certain type of wetland, and each generation teaches its young to do the same; historically, this type of habitat must be where they’ve had the most success. However, when captive-reared Whooping Cranes, free of their parents’ hang-ups, were released in Louisiana, they moved into a wide variety of human-modified habitats like agricultural fields and suburban ponds, and their flexibility has helped them succeed.

“Many animals learn some of their behavior, such as avoiding humans and choosing the right habitat, from their parents. This learning is called ‘cultural transmission of behavior.’ Usually it’s a good thing for the young,” explains Dinets. “But in our rapidly changing world, this learning of ‘traditional’ behavior can make the young animals less adaptable, for example, if they have to survive in human-modified habitats with lots of human disturbance. Animals that learn to survive by themselves, without parental guidance, might do better in such places, as illustrated by the success of the Whooping Crane reintroduction program in Louisiana.”

The Commentary goes on to describe similar results from captive-raised, reintroduced populations of storks in Japan, ibises in Spain, and geese in Hawaii–again and again, birds raised without their parents’ guidance don’t share their ancestors’ reluctance to forage and nest near humans. “Dinets challenges managers of reintroduction programs to reconsider the effects of pre-release management techniques,” adds George Archibald, co-founder of the International Crane Foundation. “This wide-ranging description of the results from an array of species will help researchers ponder future directions. As someone involved in the study of the restoration of crane populations via captive management and releases, I am acutely aware of the complexities of avian behavior and of the need for continual improvement of practices.”  Science Daily  Original web page at Science Daily