Ducks mate through a process where the male (drake) mounts the female, usually on land or water. The male duck has a unique corkscrew-shaped penis that is normally kept inside the body but is quickly ejected during mating to reach into the female's similarly spiral-shaped vagina. This mating act happens very quickly, with the male's penis ejaculating sperm in about one-third of a second. The female has control mechanisms in her vagina to limit unwanted fertilization, often preventing sperm from non-preferred males from reaching the eggs. Mating can be aggressive, with multiple males sometimes copulating with a female forcibly, but females can avoid fertilization from these by directing sperm into dead-end pockets in the vagina. Ducks also engage in various courtship behaviors before mating, including head-bobbing, feather displays, vocalizations, and physical displays to attract a mate. The pair may stay together for the season during which they mate and raise offspring. This is a complex and rapid process evolved with unique genital adaptations in both males and females for reproductive success and some level of female control over fertilization.
