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| [Note Guidelines] Photographer's Note |
The Mallard (Anas platyrhynchos), probably the best-known and most recognizable of all ducks, is a dabbling duck which breeds throughout the temperate and sub-tropical areas of North America, Europe, Asia, New Zealand (where it is currently the most common duck species), and Australia. It is strongly migratory in the northern parts of its breeding range, and winters farther south. For example, in North America it winters south to Mexico, but also regularly strays into Central America and the Caribbean between September and May.
The Mallard and the Muscovy Duck are believed be the ancestors of all domestic ducks.The mallard is 56–65 cm long, has a wingspan of 81–98 cm, and weighs 2-2 1/2 pounds. The breeding male is unmistakable, with a green head, black rear end and a yellow bill tipped with black (as opposed to the dark brown bill in females). The female Mallard is light brown, like most female dabbling ducks. However, both the female and male Mallards have distinct purple speculum edged with white, prominent in flight or at rest (though temporarily shedded during the annual summer molt). In non-breeding (eclipse) plumage the drake becomes drab, looking more like the female, but still distinguishable by its yellow bill and reddish breast.
The Mallard is a rare example of both Allen's Rule and Bergmann's Rule in birds. Bergmann's Rule, which states that polar forms tend to be larger than related ones from warmer climates, has numerous examples in birds. Allen's Rule says that appendages like ears tend to be smaller in polar forms to minimize heat loss, and larger in tropical and desert equivalents to facilitate heat diffusion, and that the polar taxa are stockier overall. Examples of this rule in birds are rare, as they lack external ears. However, the bill of ducks is very well supplied with blood vessels and is vulnerable to cold. |
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