Bird wiki:
>For other uses, see Bird (disambiguation). Many - see section below. Birds are bipedal, warm-blooded, egg-laying vertebrates characterized primarily by feathers, forelimbs modified as wings, and hollow bones. Birds range in size from the tiny hummingbirds to the huge Ostrich and Emu. Depending on taxonomic viewpoint, there are about 8,800â10,200 living bird species (plus about 120â130 that have become extinct in the span of human history) in the world, making them the most diverse class of terrestrial vertebrates.
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Duck wiki:
>For other uses, see Duck (disambiguation). Dendrocygninae Oxyurinae Anatinae Merginae Duck is the common name for a number of species in the Anatidae bird family. The ducks are divided between several different subfamilies listed in full in the Anatidae article. Ducks are mostly aquatic birds, mostly smaller than their relatives the swans and geese, and may be found in both fresh and salt water.
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