the mallard and the brown bird, reifel bird sanctuary

Mallards form pairs only until the female lays eggs, at which time she is left by the male. The clutch is 8�13 eggs, which are incubated for 27�28 days to hatching with 50�60 days to fledging. The ducklings are precocial, and can swim and feed themselves on insects as soon as they hatch, although they stay near the female for protection. Young ducklings are not naturally waterproof and rely on the mother to provide waterproofing. Mallards also have rates of male-male sexual activity that are unusually high for birds. In some cases, as many as 19% of pairs in a Mallard population are male-male homosexual.

When they pair off with mating partners, often one or several drakes will end up "left out". This group will sometimes target an isolated female duck � chasing, pestering and pecking at her until she weakens (a phenomenon referred to by researchers as rape flight), at which point each male will take turns copulating with the female. Male Mallards will also occasionally chase other males in the same way. (In one documented case, a male Mallard copulated with another male he was chasing after it had been killed when it flew into a glass window.)