Ornithologists discover three-species hybrid warbler

Nov. 7 (UPI) -- Scientists have discovered a warbler in Pennsylvania that is the hybrid of three species, a rarity.

The bird, documented by ornithologists at Cornell University, is the offspring of a hybrid mother and father from a separate genus. It's the first time scientists have identified such a reproductive trifecta.

"It's extremely rare," David Toews, a postdoctoral associate at the Cornell Lab of Ornithology, said in a news release. "The female is a golden-winged/blue-winged warbler hybrid -- also called a Brewster's warbler. She then mated with a chestnut-sided warbler and successfully reproduced."

Lowell Burket, an avid birder from Roaring Spring, Penn., first noticed the hybrid warbler last spring. He described the unusual bird on eBird.org and reached out to a researcher at Cornell.

"I tried to make the email sound somewhat intellectual so they wouldn't think I was a crackpot," Burket said. "Having the photos and video helped. Within a week researcher David Toews came down. We found the bird again and collected a blood sample and measurements."

Analysis of the blood samples confirmed the bird's novel genetic heritage. Researchers were able to identify genetic coding inherited from the bird's mother and father.

"We confirmed that the mother would have looked like a Brewster's warbler and the father was a chestnut-sided warbler," Toews said.

Hybridization among golden-winged and blue-winged warblers is common, but the two species have never before been documented mating with chestnut-sided warblers.

Hybrids are more common among populations in decline. With fewer mates to choose from, birds are sometimes forced to shack up with closely related species.

"That this hybridization occurred within a population of golden-winged warblers in significant decline suggests that females may be making the best of a bad situation," said Toews. "It also tells us that wood-warblers in general have remained genetically compatible long after they evolved major differences in appearance."

Researchers described the novel hybrid this week in the journal Biology Letters. Toews and his colleagues plan to continue monitoring the unusual bird to see how his hybrid appearance affects his ability to find his own mate.