Split down the middle, with one side flaunting yellow ‘wing pits’, and the other side rocking a pink underwing, researchers say this spectacular-looking songbird is one for the record books.
While we can’t be sure without a blood test or an autopsy, the team says this rose-breasted grosbeak (Pheucticus ludovicianus) is probably the product of a genetic anomaly known as bilateral gynandromorphy, one we’ve seen in birds before.
Unlike true hermaphroditism, which refers to having both male and female reproductive tissues, gynandromorphs display contrasting sexual characteristics on each side of their body.
In this case, while one side of the rose-breasted grosbeak appears genetically female, the other side shows all the hallmarks of a genetic male.
Even the backs of its wings and tail show crucial sexual differences, with the left side displaying a browner shade and the right side a blacker one.
If the bird is anything like other gynandromorphs we’ve found, this left-right division might go for its insides, too, including its brain and its reproductive organs.
“The entire banding team was very excited to see such a rarity up close, and are riding the high of this once-in-a-lifetime experience,” says the program manager Annie Lindsay.
“One of them described it as ‘seeing a unicorn’ and another described the adrenaline rush of seeing something so remarkable.”