This healthy, 1-year-old male offspring of a rose-breasted grosbeak and scarlet tanager is the first-ever documented hybrid of its kind. The two species have such divergent nesting preferences that they have been on independent evolutionary trajectories for at least 10 million years — until now.
Stephen Gosser / Penn State University
Stephen Gosser / Penn State University
This healthy, 1-year-old male offspring of a rose-breasted grosbeak and scarlet tanager is the first-ever documented hybrid of its kind. The two species have such divergent nesting preferences that they have been on independent evolutionary trajectories for at least 10 million years — until now.
Penn State researchers have identified a rare hybrid of two western Pennsylvania songbirds.
The bird is a combination of the rose-breasted grosbeak and brightly-colored scarlet tanager. Stephen Gosser—a self-described “diehard birder”— spotted it in Lawrence County, along the Commonwealth’s western edge, in June 2020.
But while the rose-breasted grosbeak tends to nest along the open edges of woodlands, tanagers prefer mature forest canopies. Scientists consider the two species highly divergent; they last shared a common ancestor over 10 million years ago.
“So it seemed very unlikely, and it’s never been recorded before,” PSU researcher David Toews told WESA’s The Confluence on Monday.
An assistant professor of biology, Toews identified the rare hybrid bird with genomic sequencing and song analysis. It’s the first documented bird of its kind.
Toews, alongside researchers from the University of Pittsburgh and the National Aviary, published a confirmation of the bird hybrid in the journal Ecology and Evolution this summer.
The team also used comparative genetic markers to determine that the rose-breasted grosbeak was the bird’s female parent. That’s because mitochondrial DNA is only inherited from the mother. Researchers looked specifically at that sequence in the hybrid bird’s cells to determine its lineage.
The bird’s father, on the other hand, was the scarlet tanager.
“Their plumage is something that they use to distinguish each other, so they’re usually pretty good at choosing mates that are their own species,” Toews explained. “While mistakes happen, it’s not quite as common.”
The hybrid bird was originally identified after Gosser—the Pittsburgh-area bird enthusiast—heard it singing the scarlet tanager’s song.
The team at Penn State will continue to look for hybrid species in other birds, and compare this bird’s genome to other “odd” avian hybrids.
“I’m sure some of them will turn out to be interesting cases like this one,” Toews said.
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