Audubon's Warbler "Borrowed" DNA to Fuel Bird Migration

Could a common songbird have "borrowed" DNA? That's what scientists are claiming. They've found that a bird may have acquired genes from fellow migrating birds in order to travel greater distances.

Most species of birds either migrate or remain resident in one region. Yet the Audubon's warbler is a bit different in that regard. This bird actually exhibits different behaviors in different locations. For example, the northern populations breed and then migrate south for the winter while the southern populations have a tendency to stay put all year long.

This particular mystery thickens when you take the myrtle warbler into account. In the past, researchers have found that Audubon's warblers share the same mitochondrial DNA (mtDNA) with myrtle warblers even though they look dramatically different. Since mitochondria are only passed down from mothers to their offspring, this is particularly surprising.

In order to learn a bit more about these birds, the researchers analyzed genetic data and stable isotopes in feathers. They also analyzed the oxygen consumption in mitochondria in their flight muscles. In addition, the scientists pinpointed the exact location near the Utah-Arizona border where the myrtle warblers' "wanderlust" genes displace the Audubon warbler's ancestral mitochondria.

"Because of its prominent role in reconstruction evolutionary relationships, people often forget that mitochondria actually have a very important function as the main energy generator of cells," said David Toews, one of the researchers, in a news release. "Our findings suggest that over generations, the Audubon's warbler may have co-opted the myrtle's mitochondria to better power its own travels."

The findings reveal a little bit more about these unusual birds. In addition, they show exactly how these creatures manage to both remain stationary and travel vast distances.

The findings are published in the journal Evolution.