A Rare Hybrid Bird Sheds Light On Evolution's "Mistakes" : Short Wave When Steve Gosser heard the song of a scarlet tanager in the woods, he knew to look for a bright-red bird with black wings. But when he laid eyes on the singer, he saw instead a dark-colored head, black-and-white body, with a splash of red on its chest. "Well, that sort of looks like a first-year male rose-breasted grosbeak," he said. The song of one bird coming out of the body of another suggested this little guy could be a rare hybrid. Gosser enlisted the help of some pros, including biologist David Toews, who conducted a genetic analysis to see if this was truly the offspring of two species that diverged 10 million years ago, and today run in very different circles. On today's episode, Gosser and Toews fill Aaron in on this avian mystery, and what hybrid animals can teach us about evolution.

He Had His Father's Voice: Tracking A Rare Bird Hybrid

He Had His Father's Voice: Tracking A Rare Bird Hybrid

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A Scarlet Tanager perches on a branch. In the Neversink Mounatin Preserve in Lower Alsace Township Tuesday afternoon June 22, 2021. Ben Hasty/MediaNews Group/Reading Eagle via Getty Images hide caption

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Ben Hasty/MediaNews Group/Reading Eagle via Getty Images

A Scarlet Tanager perches on a branch. In the Neversink Mounatin Preserve in Lower Alsace Township Tuesday afternoon June 22, 2021.

Ben Hasty/MediaNews Group/Reading Eagle via Getty Images

When Stephen Gosser heard the song of a scarlet tanager in the Pennsylvania woods near his home, he knew just what to look for: a bright-red bird with black wings. As a self-described "diehard birder," Gosser had seen and photographed plenty of them. But when he laid eyes on the singer, what he saw surprised him: a dark-colored head, black-and-white body, with a splash of red on its chest. "Well, that sort of looks like a first-year male rose-breasted grosbeak," he said, recounting the tale for Short Wave's Aaron Scott.

The song of one bird coming out of the body of another: it suggested that this little guy could be a rare hybrid. So Gosser enlisted the help of some pros, including biologist David Toews of Pennsylvania State University. Toews and his collaborators conducted a genetic analysis to see if this was truly the offspring of a scarlet tanager and a rose-breasted grosbeak – two species that diverged 10 million years ago, and today run in very different circles.

On today's episode, Gosser and Toews fill Aaron in on this avian mystery, and what hybrid animals can teach us about evolution.

You can find the birdsongs in this episode here.

This episode was produced by Aaron Scott and Margaret Cirino. Gabriel Spitzer was the editor. Brit Hanson checked the facts. The audio engineer was Stu Rushfield.