How do Robins (Bird) Mate?
Male robins do not have penises. They and the females both have what’s called a “cloaca,” which is basically the main exit to the body’s various highways. The digestive tract ends in the cloaca, and robins’ kidneys dump out in the cloaca (the white part of bird poop is really pure urea, which is mixed with water in mammals to make urine). And the reproductive tract ends with the cloaca, too. So what happens is a male robin puts his cloaca against a female’s (this is called a “cloacal kiss,” in case you were wondering). The male ejaculates sperm through his cloaca and it is taken up into the female’s cloaca and then into the uterus, where it fertilizes her eggs. Some birds do have penises, but they’re crazy weird, and not at all like you’d think they’d be.