Osprey - WikiHQ

The osprey (; Pandion haliaetus), historically known as 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 in length and a wingspan of . It is brown on the upperparts and predominantly greyish on the head and underparts.

The osprey is distributed on all continents except Antarctica, but in South America, it occurs only as a nonbreeding migrant. It lives in a wide variety of habitats and nests in locations near a body of water providing an adequate food supply. It has specialised physical characteristics and unique behaviour in hunting its prey, which consists almost exclusively of fish.

Taxonomy

The osprey was described in 1758 by Carl Linnaeus under the name Falco haliaetus in his 10th edition of Systema Naturae. Linnaeus specified the type locality as Europe, but in 1761, he restricted the locality to Sweden.

The osprey is the only extant species placed in the genus Pandion that was introduced by French zoologist Marie Jules César Savigny in 1809. The genus is the sole member of the family Pandionidae.

The osprey is unusual in that it is a sole living species that occurs nearly worldwide. Even the few subspecies are not unequivocally separable. Generally, four subspecies are recognised, although differences are small, and ITIS lists only the first three.

P. h. haliaetus <small>(Linnaeus, 1758)</small> – the Eurasian osprey is the nominate subspecies that occurs across the Palearctic realm and several parts of sub-Saharan Africa from the Azores and the Iberian Peninsula east to Japan and Kamchatka Peninsula, throughout South and Southeast Asia, the Indian subcontinent, Madagascar, and much of the African coastline. Another Pandionidae claw fossil was recovered from Early Oligocene deposits in the Mainz basin, Germany, and was described in 2006 by Gerald Mayr. comes from Greek haliáetos "sea-eagle" (also haliaietos) from the combining form hali- of hals "sea" and aetos, "eagle".

The origins of "osprey" are obscure; A short tail and long, narrow wings with four long, finger-like feathers, and a shorter fifth, give it a very distinctive appearance. 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. The species rarely scavenges dead or dying fish.

Occasionally, the osprey may prey on rodents, rabbits, hares, other mammals, snakes, turtles, frogs, birds, salamanders, conchs, and crustaceans.

File:Osprey with Rainbow Trout.jpg|American osprey with rainbow trout

File:Osprey Fish Nictitating.png|American osprey with American gizzard shad

File:Pandion haliaetus -San Francisco Bay, California, USA-head-8 (2).jpg|American osprey with scraps of fish on its beak

File:WesternOsprey (cropped).jpg|Eurasian osprey feeding on a fish in Kartung, the Gambia: Characteristically, its tongue often pokes out whilst swallowing food.

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Adaptations

The osprey has several adaptations that suit its piscivorous lifestyle. These include reversible outer toes,thumb|American ospreys preparing to mate on the nest

Reproduction

thumb|Eurasian osprey standing next to its nest showing their relative sizes

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 14 or so similar nesting sites are known, 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.

Generally, ospreys reach sexual maturity and begin breeding around the age of three to four, though in some regions with high osprey densities, such as Chesapeake Bay in the United States, they may not start breeding until five to seven years old, and a shortage of suitable tall structures may exist. If no nesting sites are available, young ospreys may be forced to delay breeding. To ease this problem, posts are sometimes erected to provide more sites suitable for nest building.

The newly hatched chicks weigh only , but fledge in 8–10 weeks. A study on Kangaroo Island, South Australia, had an average time between hatching and fledging of 69 days. The same study found an average of 0.66 young fledged per year per occupied territory, and 0.92 young fledged per year per active nest. Some 22% of surviving young either remained on the island or returned at maturity to join the breeding population.

File:Pandion haliaetus MWNH 0705.JPG|Egg, collection of the Museum Wiesbaden

File:Osprey chicks at Back Bay National Wildlife Refuge in Virginia. (5343668960).jpg|Hatchling chicks

File:Osprey Chicks (26177677892) (cropped).jpg|5 week old chicks

File:Osprey Fledgling (16995065659) (cropped).jpg|Fledgling juvenile

File:Pandion haliaetus -San Francisco Bay, California, USA -head-8.jpg|Adult

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Migration

European breeders winter in Africa.

Mortality

Swedish ospreys have a significantly higher mortality rate during migration seasons than during stationary periods, with more than half of the total annual mortality occurring during migration. These deaths can also be categorized into spatial patterns: Spring mortality occurs mainly in Africa, which can be traced to crossing the Sahara. Mortality can also occur through mishaps with human utilities, such as nesting near overhead electric cables or collisions with aircraft.

Predation

In Florida, ospreys may be eaten by some growth stage of invasive snakes such as Burmese pythons, reticulated pythons, Southern African rock pythons, Central African rock pythons, boa constrictors, yellow anacondas, Bolivian anacondas, dark-spotted anacondas, and green anacondas.

Conservation

thumb|Adult American ospreys on a man-made nest in New Jersey, US

The osprey has a large range, covering in just Africa and the Americas, and has a large global population estimated at 460,000 individuals. Although global population trends have not been quantified, the species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e., declining more than 30% in ten years or three generations), and for these reasons, the species is evaluated as least concern.

In South Australia, nesting sites on the Eyre Peninsula and Kangaroo Island are vulnerable to unmanaged coastal recreation and encroaching urban development.

"Seahawks", another term for osprey, is also common among sports teams. The Seattle Seahawks, a professional American football team in the National Football League, received their identity from a naming contest, defeating 1,740 others. According to team general manager John Thompson, the name "shows aggressiveness, reflects our soaring Northwest heritage, and belongs to no other major league team."

Other

So-called "osprey" plumes were an important item in the plume trade of the late 19th century and used in hats including those used as part of the army uniform. Despite their name, these plumes were actually obtained from egrets. A compromise was reached in SCR 18, which was passed on the last day of the session, designating the western meadowlark as the state songbird and the osprey as the state raptor.

References

External links

UK Osprey Information Royal Society for the Protection of Birds
Osprey species text in The Atlas of Southern African Birds
Osprey – Pandion haliaetus – USGS Patuxent Bird Identification InfoCenter
Osprey Info Animal Diversity Web
USDA Forest Service osprey data
Osprey Nest Monitoring Program at OspreyWatch
Ospreys Rebound, Rely On Help From Humans Documentary produced by Oregon Field Guide
Hellgate Ospreys Bird Cam Montana Osprey Project, hosted by the Cornell Lab