Osprey Bird

The osprey bird, or more precisely the western osprey (Pandion haliaetus), is a diurnal, fish-eating bird of prey with a wide range. It is also known as the river hawk, sea hawk, and fish hawk. It is a huge raptor with a wingspan of more than 60 cm (24 in) and a length of more than 180 cm (71 in). The upper parts are brown, while the head and underparts are primarily greyish. The osprey may nest in a range of habitats, as long as there is a body of water nearby that provides enough food. It can be found across all continents excluding Antarctica, however as just a non-breeding migrant in South America.

[Image will be Uploaded Soon]

The osprey's food is virtually entirely made up of fish, as its other popular names suggest. It has specialised physical traits and behaves in a particular way to aid in hunting and catching prey. It was granted its own taxonomic genus, Pandion, and family, Pandionidae, as a consequence of these distinguishing traits. Typically, three subspecies are recognised; one of the old subspecies, cristatus, was recently accorded full species status and is now known as the eastern osprey.

[Image will be Uploaded Soon]

Taxonomy and Systematics

The osprey, Falco Haliaeetus, was among the several species identified by Carl Linnaeus in his 18th-century work Systema Naturae. Pandion has been the only genus in the Pandionidae family, and it used to only have one species, the osprey (P. haliaetus). In 1809, French biologist Marie Jules César Savigny named the genus Pandion. The species is considered global and conspecific by the majority of taxonomic authorities. The osprey is divided into two species by some authorities: the western osprey and the eastern osprey.

The osprey eagle is distinct from those other diurnal birds of prey in many ways. It has equal-length toes, reticulate tarsi, and rounded talons rather than grooved talons. Just the osprey and owl have a reversible outer toe, enabling them to grab their osprey prey with two toes in the front and two toes behind. This is especially useful when catching slippery fish. It has always been a puzzle to taxonomists, however, it is now treated as the only extant member of the Pandionidae family, with the family classified in its proper place within the order Falconiformes.

Other classification systems group it with hawks and eagles in the Accipitridae family, which could be considered the majority of the order Accipitriformes, or with the Falconidae in Falconiformes. The Sibley-Ahlquist taxonomy groups it with some other diurnal raptors in a much larger Ciconiiformes, although this creates an unnatural paraphyletic grouping.

Fossil Record

There have only been two extinct species described based on the fossil record so far. Stuart L. Warter named Pandion homalopteron in 1976 after Middle Miocene (Barstovian) fossils discovered in marine strata in southern California. Jonathan J. Becker reported the second recognised species, Pandion lovensis, in 1985, based on fossils discovered in Florida and dating to the later Clarendonian, probably reflecting a distinct branch from P. homalopteron and P. haliaetus. In Florida and South Carolina, claw fossils were discovered in Pliocene and Pleistocene deposits.

The oldest known Pandionidae fossils were discovered in Faiyum, Egypt, in the Oligocene Jebel Qatrani Formation. They are, but, insufficient to assign to a distinct genus. Gerald Mayr documented another Pandionidae claw fossil found in Early Oligocene sediments in the Mainz Basin, Germany, in 2006.

Description

The osprey weighs 0.9–2.1 kg and measures 50–66 cm in length with a wingspan of 127–180 cm (50–71 in). As a result, it is comparable in size to the largest Buteo or Falco species. The size of the subspecies is quite similar, with the nominate subspecies being 1.53 kg, P. h. carolinensis 1.7 kg and P. h. cristatus 1.25 kg. The wing chord is 38–52 cm long, the tail is 16.5–24 cm long, and the tarsus is 5.2–6.6 cm long.

The upper parts are a dark, glossy brown, with white breasts that are occasionally stained with brown and pure white underparts. The head is white, with a dark mask that reaches to the sides of the neck and covers the eyes. The transparent nictitating membrane comprises pale blue colour, and the irises of the eyes seem golden to brown. The feet are white and possess black talons, and the bill is black with a blue cere. It has a striking look with a short tail and long, narrow wings with four long, finger-like feathers and a shorter fifth. The sexes look to be very similar, however, the adult male has a thinner body and narrower wings than the female. The male's breast band is likewise weaker or non-existent, and the male's underwing coverts seem to be more evenly pale than the female's. It's easy to figure out the sex of a breeding couple, but it's more difficult with individual birds.

Buff fringes on the upper parts, streaked feathers on the head and a buff tone on the underparts are all characteristics of the young osprey. Due to wear on the upper parts, banding on the underwings and flight feathers is a stronger predictor of a juvenile bird in the spring.

Distribution and Habitat

After the peregrine osprey falcon, the osprey is the second most extensively widespread raptor species and one of just six land-birds with a global distribution. With the exception of Antarctica, it can be located in temperate and tropical regions among all continents. It breeds throughout North America from Alaska and Newfoundland south to the Gulf Coast and Florida, and winters in the southern United States and Argentina. It could be seen in the summer throughout northern Europe, including Ireland, Finland, Scandinavia, and the United Kingdom (however not Iceland), and in the winter in North Africa. It is mostly sedentary in Australia and can be seen in patches along the coast, while it is a non-breeding traveller to eastern Victoria and Tasmania.

Among its westernmost breeding location in South Australia and the next breeding grounds to the west in Western Australia, there seems to be a 1,000 km (600 mi) gap, which corresponds to the coast of the Nullarbor Plain. It can be located in Pacific islands such as the Solomon Islands, Bismarck Islands, and New Caledonia, and fossil remains of adults and juveniles were being discovered in Tonga, where it was most likely driven out by humans. It's probable it used to be found in Vanuatu and Fiji as well. This is a winter visitor to all sections of South Asia and Southeast Asia, from Myanmar to Indochina and southern China, Malaysia, Indonesia, and the Philippines.

The species' global distribution is unique for land-based birds, and that is just known in five additional species.

Diet

The osprey is a fish-eating bird, with fish accounting for 99 percent of its diet. Fish averaging 150–300 g and measuring 25–35 cm in length are usual, however, the weight might range from 50 g to 2 kg. Almost every species of fish within this size range gets captured.

The vision of ospreys is highly adapted to identifying aquatic things from the air. The osprey bird of prey initially sees prey while it is 10–40 m (33–131 ft) well above water, then hovers for a moment before plunging feet first into the water. They catch fish by plunging into bodies of water, frequently totally submerging themselves. When an osprey descends, the osprey in flight gets adjusted at an angle to compensate for the refraction-induced distortion of the fish's picture. Ospreys usually feed on surrounding perch, but they have been reported to transport fish over longer distances.

The osprey will occasionally eat rodents, hares, rabbits, other birds, and small reptiles.

Adaptations

Below Given are Some of the Adaptations That Suit the Osprey Birds Lifestyle:

• Reversible outer toes 

• On the bottom of the toes, there are spiky spicules.

• During dives, the nostrils can be closed to keep the water out.

• Scales on the talons that face backwards and serve as barbs to keep the catch in place.

• It has rich, oily plumage that keeps its feathers from becoming wet.

Reproduction

Ospreys breed close to freshwater lakes and rivers, as well as in brackish coastal seas. In Rottnest Island, off the coast of Western Australia, rocky outcrops close offshore are utilized as nesting sites. There seem to be 14 or so such nesting sites, with five to seven being used in any given year. Each season, several are renovated, and some are even in operation for over 70 years. A big stack of logs, turf, driftwood, or seaweed is erected in forks of trees, utility poles, rocky outcrops, man-made platforms, or offshore islets to form the nest. Giant nests on utility poles can be as big as 2 metres and weigh up to 135 kilogrammes, posing a fire hazard and causing power outages.

Ospreys achieve sexual maturity and start breeding across the age of three to four, however in some high-density areas, including the Chesapeake Bay in the United States, they might not start mating until they are five to seven years old, and there could be a scarcity of appropriate tall structures. When there are no suitable nesting places, juvenile ospreys may be compelled to postpone reproducing. Posts were often placed to give more ideal nesting locations to alleviate this problem. Ospreys favour transmission towers as nesting places in certain areas, such as East Germany.

Citizens United to Protect the Maurice River and Its Tributaries, Inc. produced a nesting platform design that has now been adopted as the official design of the State of New Jersey, United States. People from all over the world have used the nesting platform plans and supplies list that are available on the internet. 

Migration

Breeders from Europe spend their winters in Africa. Breeders from the United Areas and Canada spend the winter in South America, however, some remain in the southernmost states of the United States, like California and Florida. Few Florida ospreys travel to South America. Ospreys in Australasia do not migrate.

Female Swedish ospreys travel to Africa quicker than males, according to research. Throughout their autumn migration, they make more stops. Autumn has more variability in terms of timing and duration than spring. Even though they migrate primarily during the day, they occasionally fly at night, especially when crossing water and traverse an average of 260–280 km (160–170 mi) each day, with a maximum of 431 kilometres (268 mi) per day. An osprey tagged in Norway that is being watched in western India suggests that European birds might even winter in South Asia. Ospreys in the Mediterranean exhibit partial migratory behaviour, with a few birds staying local while others fly short distances.

Mortality

The death rate of Swedish ospreys is much greater during migration seasons than during stationary periods, with migration accounting for more than half of the overall annual mortality. These deaths could also be classified according to their location: Spring mortality is primarily found in Africa and is linked to traversing the Sahara desert. Mistakes with human utilities, including nesting near overhead electric cables or crashes with aircraft, could also result in death.

Status and Conservation

The osprey does have a broad range, reaching 9,670,000 km2in Africa and the Americas alone, and a population of 460,000 individuals worldwide. Although global population patterns have not yet been assessed, the species is not thought to be approaching the thresholds for the IUCN Red List's population decrease criterion, and hence is classified as Least Concern. 

Around South Australia, where historic territories in the Spencer Gulf and all along the lower Murray River have remained unoccupied for decades, there have been indications of regional decline. 

The major threats to osprey populations within the late 19th and early 20th centuries have been egg collectors and hunting of adults amongst other birds of prey, however, osprey populations declined dramatically throughout many areas in the 1950s and 1960s, which emerged to be partly due to the harmful effects of insecticides like DDT on reproduction.