How Do Birds Mate?

During breeding season in response to the hormones, the male's reproductive organs become several hundred times larger than normal to produce sperm, with the left reproductive organ usually larger. The female bird’s reproductive organs also enlarge during breeding season to produce the ovum. Usually in Females, only the left reproductive organ is functional. 

In birds, an egg is fertilized in the female bird's oviduct by a seed cell from the male bird. Once fertilized, the sperm becomes the nucleus of the egg. The egg, that has its own food source, the yolk, will be laid by the female into her nest, incubated, and then the baby bird will hatch.

But how does the sperm from the male bird get into the female? How can they have intercourse without any external male organs, such as a penis? The male's sperm, produced in the testes, passes to reproductive organs. The female bird unfans her tail, moves it to one side while the male climbs up onto her back or gets close to her. Their cloaca’s are pressed together and the seed moves from the male to the female. This act is called a cloacal kiss.

The seed is stored by the female for at least a week, in some species over a hundred days. Then as each egg from the reproductive organs moves, it gets fertilized with the stored sperm, producing a clutch of many eggs, all with the seed from that one cloacal kiss.

There are a few species of birds where the males do possess a retractable penis that can be pulled back into the bird. These birds include ostriches, cassowaries, kiwis, swans, geese, and ducks. Since waterfowl sometimes make love while in the lake or pond, the penis helps ensure that the seed is not washed away by the water.

Seed can be transferred from male cloaca to the female in a blink of an eye or less than a second. Some birds seem to want to linger longer though, sometimes having sex for more than an hour! And, although it is not necessary to copulate frequently since the seed is stored within the female, remember those hormones are still making the birds excited. Many pairs of birds will mate numerous times within a few days.

Cloaca- The posterior opening which serves as the following, intestinal, Reproductive and unitary tract of most birds, this is where all waste matter is discharged from (poop)and all copulation occurs when male and female put them together, It is found on the underside of the bird below the tail and slightly above and in between the legs.

Oviduct- The tube through which an ovum or egg passes from an ovary.

Waterfowl- Ducks, geese, or other large aquatic birds.

Incubate- To keep egss at a suitable temperature so that they develop.