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Osprey

2007 Schools Wikipedia Selection. Related subjects: Birds

                     iOsprey
   A North American Osprey preparing to dive.
   A North American Osprey preparing to dive.

                             Conservation status

   Least Concern (LC)
            Scientific classification

   Kingdom: Animalia
   Phylum:  Chordata
   Class:   Aves
   Order:   Falconiformes
   Family:  Pandionidae
            Sclater & Salvin, 1873
   Genus:   Pandion
            Savigny, 1809
   Species: P. haliaetus

                                Binomial name

   Pandion haliaetus
   (Linnaeus, 1758)

   The Osprey (Pandion haliaetus) is a medium large raptor which is a
   specialist fish-eater with a worldwide distribution. It occurs in all
   continents except Antarctica, but in South America only as a
   non-breeding migrant. It is often known by other colloquial names such
   as fishhawk, seahawk or Fish Eagle.

   An unusual bird with no close relatives, it is the only living species
   of the genus Pandion, which is in turn the only genus in the bird
   family Pandionidae.

Description

   The Osprey is 52-60 centimetres (20.5-23.6 in) long with a 152-167 cm
   (5-5.5 ft) wingspan. It has mainly white underparts and head, apart
   from a dark mask through the eye, and fairly uniformly brown
   upperparts. Its short tail and long, narrow wings with four long
   "finger" feathers (and a shorter fifth) give it a very distinctive
   appearance.

   Juvenile birds are readily identified by the buff fringes to the
   upperpart plumage, buff tone to the underparts, and streaked crown. By
   spring, wear on the upperparts makes barring on the underwings and
   flight feathers a better indicator of young birds. Adult males can be
   distinguished from females from their slimmer bodies and narrower
   wings. They also have a weaker or non-existent breast band than the
   female, and more uniformly pale underwing coverts. It is
   straightforward to sex a breeding pair, but harder with individual
   birds.

   In flight, Ospreys have arched wings and drooping "hands", giving them
   a diagnostic gull-like appearance. The call is a series of sharp
   whistles, cheep, cheep, or yewk, yewk. Near the nest, a frenzied
   cheereek!

Classification

   The Osprey differs in several respects from the other diurnal birds of
   prey, and has always presented something of a riddle to taxonomists.
   Here it is treated as the sole member of the family Pandionidae, and
   the family listed in its traditional place as part of the order
   Falconiformes. Other schemes place it alongside the hawks and eagles in
   the family Accipitridae—which itself can be regarded as making up the
   bulk of the order Accipitriformes or else be lumped with the Falconidae
   into Falconiformes. The Sibley-Ahlquist taxonomy has placed it together
   with the other diurnal raptors in a greatly enlarged Ciconiiformes, but
   this has more recently turned out to result in an unnatural
   paraphyletic classification.

Subspecies

   The Australasian Osprey is the most distinctive subspecies.
   Enlarge
   The Australasian Osprey is the most distinctive subspecies.

   There are four generally recognised subspecies, although differences
   are small, and ITIS only lists the first two.
     * P. h. haliaetus (Linnaeus, 1758) Eurasia
     * P. h. carolinensis ( Gmelin, 1788), North America. This form is
       larger, darker bodied and has a paler breast than nominate
       haliaetus.
     * P. h. ridgwayi Maynard, 1887, Caribbean islands. This form has a
       very pale head and breast compared to nominate haliaetus, with only
       a weak eye mask. It is non-migratory.
     * P. h. cristatus ( Vieillot, 1816), found around the coastline of,
       and along some large rivers within, Australia and Tasmania. The
       smallest subspecies, also non-migratory.

   Ospreys are unusual insofar as a single species occurs nearly
   worldwide. Even the few subspecies are not unequivocally separable.

Prehistoric species

   There were several prehistoric species of osprey which have been
   described from fossils:
     * Pandion sp. (Early Oligocene of Fayyum, Egypt)
     * Pandion homalopteron (Middle Miocene of California, USA)
     * Pandion lovensis (Late Miocene of Florida, USA)
     * Pandion sp. (Late Miocene/Early Pliocene of Lee Creek Mine, USA)

   P. homalopteron was very similar to the living species and possibly
   even its direct ancestor. However, the biogeography of the fossil
   ospreys has not been researched well enough to suggest a place where
   the modern Osprey originated. The genus apparently first appeared in
   the Mediterranean region, but this is not certain.

Behaviour

Diet

   The Osprey is particularly well adapted to its fish diet, with
   reversible outer 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. It locates its prey from the air, often hovering
   prior to plunging feet-first into the water to seize a fish. As it
   rises back into flight the fish is turned head forward to reduce drag.
   The 'barbed' talons are such effective tools for grasping fish that, on
   occasion, an Osprey may be unable to release a fish that is heavier
   than expected. This can cause the Osprey to be pulled into the water,
   where it may either swim to safety or succumb to hypothermia and drown.

Nesting

   The Osprey breeds by freshwater lakes, and sometimes on coastal
   brackish waters. The nest is a large heap of sticks built in trees,
   rocky outcrops, telephone poles or artificial platforms. In some
   regions with high Osprey densities, such as Chesapeake Bay, USA, most
   Ospreys do not start breeding until they are five to seven years old.
   Many of the tall structures they need to build nests on are already
   taken. If there are no nesting sites available, young Ospreys may be
   forced to delay breeding. To ease this problem, posts may be erected to
   provide more better sites.

   Ospreys usually mate for life. In spring they begin a five-month period
   of partnership to raise their young. Females lay 3–4 eggs within a
   month, and rely on the size of the nest to help conserve heat. The eggs
   are approximately the size of chicken eggs, and cinnamon colored; they
   are incubated for about 5 weeks to hatching.

   The newly-hatched chicks weigh only 50-60 g (2 oz}, but fledge within
   eight weeks. When food is scarce, the first chicks to hatch are most
   likely to survive. The typical lifespan is 20-25 years.

   European breeders winter in Africa. American and Canadian breeders
   winter in South America, although some stay in the southernmost USA
   states such as Florida and California. Australasian Ospreys tend not to
   migrate.

Conservation

   Twenty to thirty years ago, Ospreys in some regions faced possible
   extinction, because the species could not produce enough young to
   maintain the population. Since the banning of DDT in many countries in
   the early 1970s, together with reduced persecution, the Ospreys, as
   well as other affected bird of prey species have made significant
   recoveries.

Popular culture

   The Osprey is the official bird of Nova Scotia in Canada and
   Sudermannia in Sweden. It is the official mascot and team name for the
   University of North Florida and the Richard Stockton College of New
   Jersey. The bird was depicted on the 1986 series Canadian $10 note. The
   Osprey is also the mascot of the Christian Falangist Party of America

   Retrieved from " http://en.wikipedia.org/wiki/Osprey"
   This reference article is mainly selected from the English Wikipedia
   with only minor checks and changes (see www.wikipedia.org for details
   of authors and sources) and is available under the GNU Free
   Documentation License. See also our Disclaimer.
