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The avian family Anatidae, commonly called waterfowl, comprise the ducks, geese, and swans.The International Ornithological Committee (IOC) recognizes these 174 Anatidae species distributed among 53 genera, 32 of which have only one species.
The long period of evolution and shifts from one kind of waterbird lifestyle to another have obscured many plesiomorphies, while apparent apomorphies are quite often the result of parallel evolution, for example the "non-diving duck" type displayed by such unrelated genera as Dendrocygna, Amazonetta, and Cairina. For the fossil record, see below.
About one half of bird species with fovea have a single one, but uniquely in birds, [221] some, such as terns, kingfishers and hummingbirds, have a second fovea, [222] called the temporal fovea, that assists in judging speed and distance and increases visual acuity. Birds that do not have a second fovea will sometimes bob their head to improve ...
How to identify them The birds are about 20 to 22 inches long, according to Audubon, about the size of a mallard duck. Adults have long necks and legs, a color pattern of chestnut, black and gray ...
Ducks generally only have one partner at a time, although the partnership usually only lasts one year. [26] Larger species and the more sedentary species (like fast-river specialists) tend to have pair-bonds that last numerous years. [27] Most duck species breed once a year, choosing to do so in favourable conditions (spring/summer or wet seasons).
The diving ducks, commonly called pochards or scaups, are a category of duck which feed by diving beneath the surface of the water. They are part of Anatidae, the diverse and very large family that includes ducks, geese, and swans. The diving ducks are placed in a distinct tribe in the subfamily Anatinae, the Aythyini.
A bird colony is a large congregation of individuals of one or more species of bird that nest or roost in proximity at a particular location. Many kinds of birds are known to congregate in groups of varying size; a congregation of nesting birds is called a breeding colony.
Hawaiian monk seals grow to be 6-7 feet long, weigh 400-600 pounds, and can live more than 30 years. Males and females are generally the same size — the only way to tell them apart is to look at ...