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Scientists consider cross-breeding to save Australia's orange-bellied parrot from extinction

A team of environmental scientists at the University of Sydney, working with a pair of colleagues from the University of Copenhagen, are pondering possible ways to save the extremely endangered orange-bellied parrot. In their paper in the journal Molecular Ecology, the group outlines possible ideas for saving the birds, and the drawbacks of each.

As humans have encroached on lands once the domain of other creatures, the result has often been reductions in populations of native species and sometimes extinction. In this new effort, the researchers have focused their attention on orange-bellied parrots, which migrate between Tasmania and southern parts of Australia.

In recent years, their numbers have declined sharply. Even worse, their genetic diversity has dropped so low that scientists believe that without intervention, the species will go extinct within the next 15 years.

The researchers note that the obvious approach to saving the birds would not work; capturing several specimens and breeding them would lead to more birds, but their gene pool would still be too shallow to allow them to overcome diseases once they were released into the wild. The only way to save them, they point out, is to diversify their genes. And that could only be done in two ways.

The first method would involve using gene-editing tools such as CRISPR, to make changes that would likely exist in birds of the same species. The problem is that such an approach has not been done before and it is not clear if it would work. There is also the possibility of introducing unintended consequences, such as editing mistakes that could lead to hereditary cancers that might not be detected until after the birds are released into the wild.

The second method would involve attempting to breed the birds with another species of parrot, one that is close in most physical respects, such as the blue-winged parrot. The problem with this approach is it could lead to infertile offspring, or if it worked, would lead to a new sub-species, even if the offspring were bred with the original species, creating three-quarters-original breed birds, which would still be a new species—one pretty close to the original but still resulting in the original pure species' extinction, which the team is trying to prevent.

With neither approach offering a definitive positive result, the research team suggests more work needs to be done to find out if another approach might be found.