Bisexual Birds Live in Harmony With Straight Ones in Panama

Can’t we all just get along … like the mysterious bisexual Sapayoa birds that live in peace and harmony with straight birds in the Panamanian rain forest? Sharing the same tree branches for bathrooms? No matter what color their feathers are? Bisexual birds? Wait, what?

The sapayoa (Sapayoa aenigma) is a rarely-seen small, yellow-green bird that lives up its enigmatic name in a number of ways. While it looks like a flycatcher and actually catches flies, it’s not one. While it has a broad bill like a manakin, it’s not one of those either. A new study published this week in The Auk: Ornithological Advances has identified it as the New World’s only Old World suboscine, a subset of songbirds (oscines) and a passerine (three toes pointing forward and one backward for perching).

The field study, conducted by Cornell University students and alumni, found two active nests and 13 old pear-shaped nests hanging from trees over steep ravines just like those of their relatives in Africa and Asia. While monitoring the birds and the nests, the birdwatchers watched the birds doing something totally unexpected … having sex with both males and females.

Specifically, the Sapayoa males were seen mounting both the females, who were already sitting on eggs, and each other, and the mountings occurred often throughout the day. None seemed to mind and none got upset, which is unusual in the bird world where rare same-sex mountings are generally only done by dominant males and never in return. In this case, the males were seen working together to care for and feed both females and both sets of hatched chicks.

Then again, the Sapayoa aenigma can’t stop being enigmatic. Occasionally, the watchers saw the younger males bring food to the nest but not give it to the chicks, sometimes eating it themselves. This “fake feeding” could be a way for the younger males to sneak food for themselves.

Uh-oh. Perhaps all is not paradise for the bisexual birds of Panama. Jon Fjeldså of the University of Copenhagen, who led the research team says more must be learned about them.

The Sapayoa has long been a mystery bird. When my colleagues and I identified it as the only Old World suboscine in the New World in 2003, it only became more mysterious. How did it arrive in South America? Why does it resemble a manakin? And does it still behave like an Old World suboscine? I am excited to learn that it indeed does!

Despite those fly-hoarding males, it appears the Sapayoa still behave better than many humans.