Source: Jason Bittel, NATIONAL GEOGRAPHIC, 10/9/20

Researchers with a team monitoring bird populations at Powdermill Nature Reserve, in Rector, Pennsylvania, netted a surprise on September 24: a rose-breasted grosbeak with bizarre coloring. It had the bright scarlet feathers of a male grosbeak on one side of its body and the canary yellow plumage of a female on the other. When they saw the robin-size songbird’s split coloring, it was immediately clear that the grosbeak was what scientists call a bilateral gynandromorph—an animal that appears half male and half female.

For more of this story, click here.