General features ( bird )
Tagged: animal, birdThe smallest living bird is generally acknowledged to be the bee hummingbird of Cuba, which is 6.3 centimetres (2.5 inches) long and weighs less than 3 grams (about 0.1 ounce). The largest living bird is the ostrich (see photograph), which may stand 2.5 metres (8 feet) tall and weigh 135 kilograms (300 pounds). Some extinct birds were even larger: the largest of the moas of New Zealand and the elephant birds of Madagascar may have reached over 3 metres (10 feet) in height. Among flying birds, the wandering albatross has the greatest wingspan, up to 3.5 metres (11.5 feet), and the trumpeter swan perhaps the greatest weight, 17 kilograms (38 pounds). A Pleistocene condorlike bird, Teratornis incredibilis, had an estimated wingspan of about 5 metres (16.5 feet) and was by far the largest known flying bird. The ability to fly has permitted an almost unlimited radiation of birds, so that they are now found virtually everywhere on earth, from occasional stragglers over the polar ice caps to complex communities in tropical forests. In general the number of species found breeding in a given area is directly proportional to the size of the area and the diversity of habitats available. The total number of species is also related to such factors as the position of the area with respect to migration routes and wintering grounds of species that nest outside the area. In the United States, Texas and California have both the largest number of species recorded (545 and 461, respectively, including both resident and migrant species) and the largest number breeding (300 and 286). Seven hundred and seventy-five species, 650 of them breeding, have been recorded from North America north of Mexico. The figures for Europe exclusive of the erstwhile U.S.S.R. are 577 and 420, and the figures for the former Soviet states are 704 and 622. Costa Rica, with an area of only about 51,000 square kilometres (about 20,000 square miles) and a known avifauna of at least 758 species, probably has the most diversified group for its size of any country.
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