Starting life in captivity can alter the shape of birds’ wings, hampering their chances of surviving migratory flights when released into the wild, new research from the Australian National University (ANU) has shown.
Study author Dr. Dejan Stojanovic said that while captive breeding is an important conservation tool, it can lead to various physical changes in animals, including the shape of their wings.
One of the bird species examined was the critically endangered orange-bellied parrot.
Orange-bellied parrots have one of the largest and oldest breeding programs of any Australian species. To avoid extinction, their wild population is supplemented by annual releases of captive juveniles.
“Previously, we have shown that captivity can alter the wing shape of orange-bellied parrots, which we believe could make their migratory flights more difficult,” said Dr Stojanovic.
“But this new study reveals the first direct evidence that altering wing shape in captivity reduces migration success after release into the wild.”
Although all juvenile orange-bellied parrots had a low migration survival rate, captive-bred birds with modified wing shapes had a 2.7 times lower survival rate than those with an ideal “type” wing. savage”.
The study also found evidence of altered wing shapes in four other bird species in captivity, suggesting these changes may be more common in captivity than previously thought.
“This is probably just the tip of an iceberg of subtle physical changes in the bodies of captive-bred animals that, although easily overlooked, have a big impact after release,” said Dr Stojanovic.
“We need to be aware of this and find ways to mitigate the effects of captivity if we are to give our breeding programs the best chance of sustaining wild populations.”
It is not yet known why the flight feathers of birds are so changeable, or if it is due to genetics or the captive environment.
“There are also other unanswered questions: Can birds with captive wing forms revert to optimal wild form? Could flight training help? These questions need to be answered so that we can determine how to breed animals that are well adapted to life in the wild. “, said Dr. Stojanovic.
“This could become particularly important as the global extinction crisis forces more species to participate in captive breeding programs.”
The research has been published in Ecology Letters.
Dejan Stojanovic, Altered wing phenotypes of captive-bred migratory birds reduce fitness after release, Ecology Letters (2023). DOI: 10.1111/ele.14200
Provided by Australian National University
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