For Amorous Bald Eagles, a ‘Death Spiral’ Is a Hot Time

Bald eagles, aka Haliaeetus leucocephalus, seem to be models of decorum. The raptors mate for life, unless one partner dies early. Year after year most return to the same nests. Birds in some so-called monogamous species still mate with other partners; bald eagles seem not to.

But when it comes to courtship, bald eagles put the wild in wildlife.

The maneuver above—known as the cartwheel display or death spiral—is chief among their “spectacular courtship rituals,” says wildlife ecologist David Buehler of the University of Tennessee. “The two soar up to high altitude, lock talons, and tumble and cartwheel toward Earth.” They let go before reaching the ground—except when they don’t. In 2014 two adult eagles, talons locked, were found tangled in a Portland, Oregon, tree. (They eventually broke free and flew off.)

The courtship display is about “determining the fitness of your mate” and making that mate want to mate with you, Buehler says. “It’s like going out on the dance floor if you’re a really good dancer.” There are risks: The stunt could, for instance, end in a fatal crash. “It’s an interesting tension,” he says, “between succeeding with a mate and maintaining your own survival.”