The osprey (Pandion haliaetus), /ˈɒspri, -preɪ/, also called sea hawk, river hawk, and fish hawk, is a diurnal, fish-eating bird of prey with a cosmopolitan range. It is a large raptor, reaching more than 60 cm (24 in) in length and 180 cm (71 in) across the wings. It is brown on the upperparts and predominantly greyish on the head and underparts.
The osprey tolerates a wide variety of habitats, nesting in any location near a body of water providing an adequate food supply. It is found on all continents except Antarctica, although in South America it occurs only as a non-breeding migrant.
As its other common names suggest, the osprey's diet consists almost exclusively of fish. It possesses specialised physical characteristics and unique behaviour in hunting its prey. Its unique characteristics classify it in its own taxonomic genus, Pandion, and family, Pandionidae.
The osprey is the second most widely distributed raptor species, after the peregrine falcon, and is one of only six land-birds with a worldwide distribution. It is found in temperate and tropical regions of all continents, except Antarctica. In North America it breeds from Alaska and Newfoundland south to the Gulf Coast and Florida, wintering further south from the southern United States through to Argentina. It is found in summer throughout Europe north into Ireland, Scandinavia, Finland and Great Britain though not Iceland, and winters in North Africa. In Australia it is mainly sedentary and found patchily around the coastline, though it is a non-breeding visitor to eastern Victoria and Tasmania.
There is a 1,000 km (620 mi) gap, corresponding with the coast of the Nullarbor Plain, between its westernmost breeding site in South Australia and the nearest breeding sites to the west in Western Australia. In the islands of the Pacific it is found in the Bismarck Islands, Solomon Islands and New Caledonia, and fossil remains of adults and juveniles have been found in Tonga, where it probably was wiped out by arriving humans. It is possible it may once have ranged across Vanuatu and Fiji as well. It is an uncommon to fairly common winter visitor to all parts of South Asia, and Southeast Asia from Myanmar through to Indochina and southern China, Indonesia, Malaysia and the Philippines.
The osprey is piscivorous, with fish making up 99% of its diet. It typically takes live fish weighing 150–300 g (5.3–10.6 oz) and about 25–35 cm (9.8–13.8 in) in length, but virtually any type of fish from 50 g (1.8 oz) to 2 kg (4.4 lb) can be taken.[22] Even larger 2.8 kg (6.2 lb) northern pike (Esox lucius) has been taken in Russia. The species rarely scavenges dead or dying fish.
Characteristically its tongue often pokes out whilst swallowing food.
Ospreys have vision that is well adapted to detecting underwater objects from the air. Prey is first sighted when the osprey is 10–40 m (33–131 ft) above the water, after which the bird hovers momentarily and then plunges feet first into the water. They catch fish by diving into a body of water, oftentimes completely submerging their entire bodies. As an osprey dives it adjusts the angle of its flight to account for the distortion of the fish's image caused by refraction. Ospreys will typically eat on a nearby perch but have also been known to carry fish for longer distances.
Occasionally, the osprey may prey on rodents, rabbits, hares, other mammals, snakes, turtles, frogs, birds, salamanders, conchs and crustaceans. Reports of ospreys feeding on carrion are rare. They have been observed eating dead white-tailed deer and Virginia opossum.
The osprey breeds near freshwater lakes and rivers, and sometimes on coastal brackish waters. Rocky outcrops just offshore are used in Rottnest Island off the coast of Western Australia, where there are 14 or so similar nesting sites of which five to seven are used in any one year. Many are renovated each season, and some have been used for 70 years. The nest is a large heap of sticks, driftwood, turf or seaweed built in forks of trees, rocky outcrops, utility poles, artificial platforms or offshore islets. As wide as 2 meters and weighing about 135 kg (298 lb), large nests on utility poles may be fire hazards and have caused power outages.
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