Osprey

Osprey
Scientific classification
Kingdom Information
Domain	Eukaryota
Kingdom	Animalia
Subkingdom	Bilateria
Branch	Deuterostomia
Phylum Information
Phylum	Chordata
Sub-phylum	Vertebrata
Infraphylum	Gnathostomata
Class Information
Superclass	Tetrapoda
Class	Aves
Sub-class	Neornithes
Infra-class	Neoaves
Order Information
Order	Accipitriformes
Sub-order	Accipitres
Family Information
Superfamily	Accipitroidea
Family	Pandionidae
Genus Information
Genus	Pandion
Species Information
Species	P. haliaetus
Population statistics
Population	500,000+ (2016 est.)
Conservation status	Least concern

The osprey, or fish hawk (Pandion haliaetus), is a bird of prey within the family Pandionidae. What makes the Osprey unique compared to other falcons are their beautiful coloring patterns and their useful opposable toe. The migratory Osprey can be found on every continent except for Antarctica, usually choosing to make their nests on high perches up above a body of water. Their diet consists of almost completely fish, which they dive for.

Anatomy

A perfect representation of the osprey's unique anatomy.

As one of the largest birds in North America, the osprey has a large six-foot wingspan and a body that is nearly two feet long, but has an average weight of only 2-4lbs. The female Osprey's body tends to be slightly larger than the males. They have a curved beak and a small head with the eyes set towards the beak. The Osprey's legs are very strong, with long talons for catching and gripping fish. The Osprey's can be recognized by its white breast and belly, black back and long black wings, dark eyestripes, and a white crown. The Juvenile Osprey's color is similar to the adults, the only differences being white back feathers, fewer markings on the breast, and orange eyes. [1]

What sets the Osprey apart from the other Falconiformes is that they have an opposable toe that can either face forward or backwards, helping greatly when attempting to grab a slippery fish. Instead of one talon on one side of the fish and three on the other, the Osprey is able to have two talons gripping either side.

Subspecies

Although called fish hawk, recent molecular genetic studies have confirmed the special status of the osprey within the order Accipitriformes, placed in a separate family Pandionidae. Although debate is ongoing, researchers have come to the conclusion that all four subspecies should be considered as species in their own right. Indeed, Australian authorities have, with some justification, granted full species status to P. h. cristatus as the eastern osprey, Pandion cristatus .

• Pandion haliaetus carolinensis; Canada to southern United States; winters south to Peru and Brazil
• Pandion haliaetus cristatus; coastal Australian mainland, Sulawesi, Java, New Guinea, New Caledonia
• Pandion haliaetus haliaetus; Palearctic Eurasia; winters to South Africa, India and Philippines
• Pandion haliaetus ridgwayi; Caribbean, including Bahamas, Cuba and Belize

Name

The word "osprey" has its roots in the Middle English word ospray, which was carried over in the 15th century from the Anglo-French osfraie, based in turn upon the Latin ossifraga, which means "bone-breaker"; this apparently was referring to a superficial resemblance between it and a bird then called the ossifrage, which is today known as the lammergeier or bearded vulture (Gypaetus barbatus); unlike the osprey, the lammergeier is known to break up and consume bones. The species genus name commemorates a king of Greek mythology, Pandion.

Mentioned in Leviticus 11:13 and Deuteronomy 14:12, the osprey was not to be consumed by the Hebrews as it was considered an unclean animal.

Reproduction

The Osprey is sexually mature near 3 years old, but sometimes may not breed until the age of 5 where population is low. Osprey courtship begins at food and nest locations. Often the male Osprey preforms an aerial show to impress the female, this act is also meant to intimidate other male Osprey. Once a mate is chosen, both male and female Osprey collect building material for the nest. After the nest is completed, the male begins to hunt fish to bring back to the female in the nest. The females that receive the greatest amount of food are more likely to breed with their mate and less likely to go out in search of another male. Most of the time Ospreys are monogamous (only having one mate), but when two nests are close enough so that the male can support two females, polygamy occurs (having more than one mate).

Breeding seasons of Ospreys are dependent on whether or not the Osprey migrates seasonally. Those that do not breed in the winter and the spring breed during the spring and summer. Once the female lays her eggs (usually 2 to 4), both sexes incubate the egg, and after around 40 days, they hatch. Both sexes of Osprey care for their chicks by protecting them from potential predators, harsh weather, and by supplying food (up to 10 fish a day). The parents supply the young with food for up to 8 weeks.[2]

Ecology

An Osprey has placed its nest high in a tree.

Ospreys can be found all over the world in every continent except for Antarctica. The four species of Osprey are classified based on what season and place they breed in. They are able to live almost anywhere but tend to make their nest near or above a body of water, such as lakes, rivers, marshes, mangroves, and seashores. Their nest is made up of sticks and other assorted materials and is normally located on elevated platforms such as trees, cliffs, power poles, or bridges. The Osprey is known to once in a while make its home on the ground level, but not often in order to avoid confrontation with the predators that stalk the Earth.

The Osprey's diet consists of 99% fish and 1% small land animals, which is quite unusual for birds of prey. They will eat practically any and all fish they are able to find, with more than 80 species of fish seen being eaten by Osprey. Osprey hunt for fish while in flight as opposed to a perch, and when they locate a fish, they hover, then dive feet-first into the water. The Osprey is fully engulfed in water, grabs the fish, then emerges from the water using its strong wings. While in the air, the Osprey utilizes its unique toe to reposition the fish to a more aerodynamic position. The Osprey then returns to its nest and eats the fish. They do not need a large amount of water because the fish supplies most of the water they need.

Young Osprey are subject to predation by Bald Eagles and Great Horned Owls, but their feathers are spotted, giving the chicks some useful camouflage. Climbing animals such as raccoons and snakes are also known to prey upon the eggs of Osprey, but Osprey do not represent a significant source of food for any creature. It used to be thought that Osprey competed with man for fish, but it is now known that Osprey do not feed on such a significant number of fish to affect the casual fisherman, much the less industrial level. [3]

Communication

Ospreys use a variety of forms of communication, including 5 different calls, aerial acrobatics, and body postures. Osprey use the diverse calls to beg for food, to warn other Osprey, courtship during mating seasons, and to defend their home. During mating season, each male Osprey performs a series of flights and calls while grasping a fish in its beak. Calls are also implemented when an Osprey has spotted a potential predator or when a creature approaches the nest as a kind of warning.

Threats

Historically, the osprey has been threatened with extinction, with hunting and collecting cited for the species decline in much of Europe, and the use of pesticides (principally DDT) in North America which accounted for a 90% loss of the species population. An overall reduction of these factors combined with a ban on DDT in the early 1970s - aided by the bird's ability to tolerate nearby human activity - has enabled a comeback. Still, occasional shooting and windfarms have been cited as current threats.

References

• [4] The Peregrine Fund.
• [5] Unknown, Wikipedia, 2011.
• [6] Kirschbaum, K. and P. Watkins, Animal Diversity Web, 2000.