tisdag 2 februari 2010

312. Tre

Tisdagstema Liggande
Outdoor Wednesday

The Mallard - the best-known and most recognizable of all ducks, is a dabbling duck Anas platyrhynchos

The Mallard inhabits most wetlands, including parks, small ponds and rivers, and usually feeds by dabbling for plant food or grazing; there are reports of it eating frogs. It usually nests on a river bank, but not always near water. It is highly gregarious outside of the breeding season and will form large flocks, which are known as a sord.[6]
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 fledgling. 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.

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 said male had been killed when he flew into a glass window

It was generally assumed that as the spectacular nuptial plumage of Mallard drakes is obviously the result of sexual selection - most species in the mallard group being sexually monomorphic -, hybrid matings would preferentially take place between females of monomorphic relatives and Mallard drakes instead of the other way around. But this generalization was found to be incorrec.
With help from Wikipidia.

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