A yellow, black, and white bird spotted in a backyard in Pennsylvania earlier this year turned out to be a hybrid of three different species.
When bird watcher Lowell Burket saw the male bird in the borough of Roaring Spring in May, he noticed that it had the physical attributes of the blue-winged warbler and the golden-winged warbler, the Huffington Post reported. The bird, however, sang like a third species, the chestnut-sided warbler.
After taking photos and videos of the bird, Burket contacted the Fuller Evolutionary Biology Lab at Cornell. The lab fortunately took notice of his email and researcher David Toews got in touch with him
The two took blood samples and measurements of the bird when they found it again. DNA analysis now reveals that Burket’s suspicion about the bird was right.
It is three species in one. The bird’s mother was a hybrid between blue-winged warbler and golden-winged warbler, while the father was a chestnut-sided warbler.
In a press release published by the Cornell Lab of Ornithology, Toews explained that they looked at the genes that code for different warbler colors so they can recreate what the bird’s mother would have looked like. He explained that this is the avian equivalent of a detective’s facial composite generated with the help of genes.
Hybridization commonly occurs among Blue-winged and Golden-winged Warblers, but prior to Burket’s find, hybridization was not recorded between these species and the Chestnut-sided warblers.
“It’s extremely rare,” Toews said. “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.”
This kind of hybridization is a rare event, but it may occur more often in declining warbler populations because of a smaller pool of mates to choose from.
Toews explained that hybridization in declining population of Golden-winged warblers suggests that the females of the species could be making the best of a bad situation.
Toews also said that this suggests that warblers in general are reproductively compatible long after they independently evolved major differences in appearance.
“It tells us that warblers in general appear to be reproductively compatible over millions of years of independent evolution,” Toews told Gizmodo.
“The things that really define them, their distinct colors and their songs, are likely mating barriers, and that they don’t interbreed because they can’t, but because they choose not to.”
The findings were published in the journal Biology Letters on November 7.