AskDefine | Define osprey

Dictionary Definition

osprey n : large harmless hawk found worldwide that feeds on fish and builds a bulky nest often occupied for years [syn: fish hawk, fish eagle, sea eagle, Pandion haliaetus]

User Contributed Dictionary

commons Pandion haliaetus



Late Middle English ospray from Latin ossifragus ("bone-breaker").



  1. A bird of prey (Pandion haliaetus) that feeds on fish and has white underparts and long, narrow wings each ending in four finger-like extensions.
    • 1594: I will provide thee of a princely osprey. — Peele, Battle of Alcazar
    • c. 1612-13: But (oh Jove!) your actions, / Soon as they move, as ospreys do the fish, / Subdue before they touch. — Shakespeare, Fletcher, Two Noble Kinsmen




Extensive Definition

The Osprey (Pandion haliaetus), also known colloquially as seahawk, fish hawk or fish eagle, is a diurnal, fish-eating bird of prey. It is a large raptor, reaching 60 centimetres (24 in) in length with a 1.8 metre (6 ft) wingspan. It is brown on the upperparts and predominantly whitish on the head and underparts, with a brownish eyepatch and wings.
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 has evolved specialised physical characteristics and exhibits some unique behaviours to assist in hunting and catching prey. As a result of these unique characteristics, it has been given its own taxonomic genus, Pandion and family, Pandionidae. Four subspecies are usually recognised. Despite its propensity to nest near water, the Osprey is not a sea-eagle.


The Osprey was one of the many species described by Carolus Linnaeus in his 18th century work, Systema Naturae, and named as Falco haliaeetus. The genus Pandion was described by the French zoologist Marie Jules César Savigny in 1809.


The Osprey is 1.4–2 Kilograms (3.0-4.4 lb) in weight and 52–60 centimetres (20–24 in) long with a 150–180 centimetres (5–6 ft) wingspan. The upperparts are a deep, glossy brown, while the breast is white and sometimes streaked with brown, and the underparts are pure white. The head is white with a dark mask across the eyes, reaching to the sides of the neck. A short tail and long, narrow wings with four long, finger-like feathers, and a shorter fifth, give it a very distinctive appearance.
Juvenile Osprey may be identified by buff fringes to the plumage of the upperparts, a buff tone to the underparts, and streaked feathers on the head. During spring, barring on the underwings and flight feathers is a better indicator of a young bird, due to wear on the upperparts.
In flight, the Osprey has arched wings and drooping "hands", giving it a gull-like appearance. The call is a series of sharp whistles, described as cheep, cheep or yewk, yewk. Near the nest, the call is a frenzied cheereek!

Distribution and habitat

The Osprey has a worldwide distribution and 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 Scandinavia and Scotland, 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 1000 km 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.



Fish comprise 99 percent of the Osprey's diet. It typically takes fish weighing 150–300 grammes (5–10 oz) and about 25–35 centimetres (10–14 in) in length, but the weight can range from 50 to 2000 grammes (2–68 oz).
Prey is first sighted when the Osprey is 10-40 metres (32-130 ft) above the water, after which the bird hovers momentarily then plunges feet first into the water. It is able to dive to a depth of one metre (3.3 ft). The angle of entry into the water varies with the nature of the prey; steeper, slower dives are used when pursuing deeper, slow-moving fish, while long, quick dives are used for faster surface fish. After catching the fish considerable effort is needed to get airborne again. As it rises back into flight the fish is turned head-forward to reduce drag.
The Osprey is particularly well adapted to this diet, with reversible outer toes, sharp spicules on the underside of the toes, closable nostrils to keep out water during dives, and backwards-facing scales on the talons which act as barbs to help hold its catch. Rarely, the Osprey may prey on other wetland animals, such as aquatic rodents, salamanders, other birds, and small reptiles.


Ospreys usually mate for life. Rarely, polyandry has been recorded. The eggs are incubated for about 5 weeks to hatching.
The newly hatched chicks weigh only 50–60 grammes (2 oz), 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. When food is scarce, the first chicks to hatch are most likely to survive. The typical lifespan is 20–25 years. In North America Bubo owls and Bald Eagles (and possibly other eagles of comparable size) are the only major predators of both nests and sub adults.


European breeders winter in Africa. American and Canadian breeders winter in South America, although some stay in the southernmost U.S. states such as Florida and California. Australasian Ospreys tend not to migrate.
Studies of Swedish Ospreys showed that females tend to migrate to Africa earlier than the males. More stopovers are made during their autumn migration. The variation of timing and duration in autumn was more variable than in spring. Although migrating predominantly in the day, they sometimes fly in the dark hours particularly in crossings over water and cover on average 260-280 km/day with a maximum of 431 km/day.


The Osprey has a large range, covering 9,670,000 km² (3.7 million square miles) 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. The pesticide interfered with the bird's calcium metabolism which resulted in thin-shelled, easily broken or infertile eggs. The Roman writer Pliny the Elder reported that parent Ospreys made their young fly up to the sun as a test, and dispatch any that failed. Another odd legend regarding this fish-eating bird of prey, derived from the writings of Albertus Magnus and recorded in Holinshed's Chronicles, was that it had one webbed foot and one taloned foot. There was a medieval belief that fish were so mesmerised by the Osprey that they turned belly-up in surrender, and as such has been featured on more than 50 postage stamps.
osprey in Arabic: شماط
osprey in Bulgarian: Орел рибар
osprey in Czech: Orlovec říční
osprey in Welsh: Gwalch y Pysgod
osprey in Danish: Fiskeørn
osprey in German: Fischadler
osprey in Spanish: Pandion haliaetus
osprey in Esperanto: Fiŝaglo
osprey in Basque: Arrano arrantzalea
osprey in French: Balbuzard pêcheur
osprey in Western Frisian: Fiskearn
osprey in Galician: Aguia peixeira
osprey in Croatian: Orao ribič
osprey in Ido: Mar-aglo
osprey in Indonesian: Elang Tiram
osprey in Italian: Pandion haliaetus
osprey in Hebrew: שלך
osprey in Lithuanian: Erelis žuvininkas
osprey in Dutch: Visarend
osprey in Japanese: ミサゴ
osprey in Norwegian Nynorsk: Fiskeørn
osprey in Polish: Rybołów
osprey in Portuguese: Águia-pescadora
osprey in Russian: Скопа
osprey in Simple English: Osprey
osprey in Slovak: Kršiak rybožravý
osprey in Slovenian: Ribji orel
osprey in Finnish: Sääksi
osprey in Swedish: Fiskgjuse
osprey in Turkish: Balık kartalı
osprey in Chinese: 鹗
osprey in Contenese: 魚鷹
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