Animal sex: How birds do it

white birds dancing on snow
Japanese Red Crown Cranes (Grus japonensis) are dancing together at Japane's Tsurui Ito Tancho Crane Sanctuary. These cranes form stable, monogamous bonds and perform such duets to compete for scarce resources. (Image credit: DoctorEgg/Getty)

Sure, birds can fly, but how do they have sex? Can they do it in the air? And where do they keep their reproductive organs?

For humans to understand bird sex, they must first throw out all thoughts of mammalian sex organs. Unlike mammals, most male birds do not have penises, according to Ornithology.com (opens in new tab), a website run by Roger Lederer, professor emeritus of biological sciences at California State University, Chico. 

Instead, both male and female birds have what's known as a cloaca.

The cloaca is an internal chamber that ends in an opening, and through this opening, a bird's sex organs — testes or ovaries — discharge sperm or eggs. This same opening also serves another purpose: the expulsion of urinary and digestive waste.

During mating seasons, the cloacal openings of both male and female birds swell, protruding slightly outside their bodies. When birds are feeling frisky, they rub their swollen cloacas together. The male's sperm, which has been stored in his cloaca, is deposited into the female's cloaca, where it travels up the chamber and eventually fertilizes an egg.

Though the process of avian insemination is similar to that of humans and other mammals, you won't be seeing a birdie Kama Sutra anytime soon: Birds typically have sex in only one position. And despite rumors to the contrary, it isn't possible for birds to have sex while in flight.

Usually, the male perches on top of the female, who moves her tail feathers to the side to expose her cloaca, according to Ornithology.com. Arching back, the male rubs his cloaca against hers.

This delicate balancing act can often take several attempts before resulting in successful copulation. Perhaps for fun — or to increase the chance of insemination — birds often have sex many times throughout the course of their mating period.

Prior to mating, birds engage in many different types of courtship rituals. Some perform dances or death-defying nose-dives, others feather nests for their prospective partners, while still others perform impressive ornithological arias to snag a mate, according to Birdspot.co.uk (opens in new tab), a website for bird lovers.

Additional resources

Watch fascinating videos of bird mating dances from the Audubon society (opens in new tab). Learn more about courtship rituals from the Royal Society for the Protection of Birds (opens in new tab). See images of the most unique courtship dances from National Geographic (opens in new tab).

This article was updated on Nov. 3, 2022 by Live Science managing editor Tia Ghose.

Elizabeth is a former Live Science associate editor and current director of audience development at the Chamber of Commerce. She graduated with a bachelor of arts degree from George Washington University. Elizabeth has traveled throughout the Americas, studying political systems and indigenous cultures and teaching English to students of all ages.