Ospreys are large birds of prey (55 to 58 cm long), with a wingspan ranging from 145 to 170 cm. Their long wings have a characteristic bend at the carpal ("wrist") joints. They are bright white underneath, with dark brown patches at the carpal joints and a mottled dark brown necklace. Other identifying markings include a dark stripe through each eye, and a dark brown back. The feet of this species are pale blue-gray, and the beak is black. Juvenile ospreys resemble adults, but have a somewhat speckled appearance due to buff-colored tips on their dark brown upper-wing and back coverts and a less well-defined necklace. Juveniles also have an orange-red iris, rather than the yellow iris that is typical of adults. Juvenile plumage is replaced by adult plumage by 18 months of age.
On average, while not necessarily longer, female ospreys are 20% heavier than males and have a wingspan that is 5 to 10% greater. In North America, for example, male ospreys range in mass from 1200 to 1600 g, whereas females range from 1600 to 2000 g. Female ospreys also often have darker plumage and a more defined necklace than their male counterparts.
Ospreys display morphological variation by region. Tropical and subtropical individuals tend to be smaller than individuals that breed at higher latitudes. The four subspecies of ospreys show some variation in size and color. Pandion haliaetis haliaetus and P.h. carolinensis are the largest and darkest subspecies. P.h.ridgwayi is approximately the same size as carolinensis, but is paler on the head and breast. P.h. cristatus is the smallest subspecies, with a dark necklace and pale crown.
Ospreys have several morphological adaptations to their unique fish-eating lifestyle. These adaptations include relatively long legs for a raptor, spiny footpads called spicules, long, sharp, curved claws, and a reversible outer toe to aid in gripping slippery fish. In addition, ospreys have dense oily plumage and efficient nasal valves that prevent water from entering the nostrils when the bird dives to catch a fish.
Range mass: 1200 to 2000 g.
Range length: 55 to 58 cm.
Range wingspan: 145 to 170 cm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: female larger; sexes colored or patterned differently
Ospreys are a relatively long-lived bird species. The oldest known osprey in North America was a 25-year old male. The oldest known female was 23 years old. However, very few individuals live to this age. Chance of survival from one year to the next varies between populations, but is estimated to be approximately 60% for young ospreys (less than 2 years old) and 80 to 90% for adult ospreys.
Range lifespan
Status: wild: 25 (high) years.
Average lifespan
Status: wild: 314 months.
Ospreys have a wide distribution because they are able to live almost anywhere where there are safe nest sites and shallow water with abundant fish. Nests are generally found within 3 to 5 km of a water body such as a salt marsh, mangrove (Rhizophora) swamp, cypress (Taxodium) swamp, lake, bog, reservoir or river. The frequency with which each of these habitat types is used varies by geographic region.
Ospreys choose structures that can support a bulky nest, and that are safe from ground-based predators. Nest sites can be safe from predators either by being difficult for a predator to climb (e.g. on a cliff) or by being over water or on a small island. Over-water nest sites that are often used by ospreys include buoys and channel markers, dead trees and artificial nest platforms. Ospreys have also been known to nest on various man-made structures, such as power poles, duck blinds, communication towers, buildings and even billboards. In many cases, nests that are built on artificial structures such as nest platforms and power poles are more stable and fledge more chicks per breeding season than nests on naturally-occuring structures.
Habitat Regions: temperate ; tropical ; terrestrial ; saltwater or marine ; freshwater
Terrestrial Biomes: forest ; rainforest ; mountains
Aquatic Biomes: lakes and ponds; rivers and streams; coastal ; brackish water
Wetlands: marsh ; swamp
Other Habitat Features: suburban ; riparian ; estuarine
Ospreys have a worldwide distribution, wintering or breeding on every continent except Antarctica. Ospreys are not known to breed in South America or Indo-Malasia, but are sometimes found there in the winter. Ospreys are winter breeders in Egypt and some Red Sea islands. Regions where ospreys are particularly abundant include Scandinavia and the Chesapeake Bay region of the United States.
There are four subspecies of ospreys, which are separated by geographic region. Pandion haliaetus carolinensis breeds in North America and the Caribbean, and winters in South America. P. h. haliaetus breeds in the Palearctic region (Europe, north Africa and in Asia, north of the Himalayas) and winters in south Africa, India and the East Indies. P. h. ridgwayi is a non-migratory subspecies. It resides in the Caribbean, with a range that extends from the Bahamas and Cuba to southeast Mexico and Belize. The final subspecies, P. h. leucocephalus is also a non-migratory subspecies. Its range includes Australia and the southwest Pacific.
Biogeographic Regions: nearctic (Native ); palearctic (Native ); oriental (Native ); ethiopian (Native ); neotropical (Native ); australian (Native ); oceanic islands (Native )
Other Geographic Terms: holarctic ; cosmopolitan
Ospreys are unusual among raptors for being piscivores. Their diet consists almost exclusively of fish (≥99% of prey items). They are generally opportunistic, and will eat whatever fish species are accessible to them – either in shallow waters, or near the surface of deeper waters. Studies in North America have documented more than 80 different prey species of ospreys. However, 2 or 3 common species may dominate the diet of local ospreys in a given area.
Ospreys hunt for fish on the wing (less often from a perch), flapping and gliding 10 to 40 meters above the water. When an osprey spots a fish, it hovers briefly, then dives toward the surface of the water. Just before hitting the water, the osprey swings its legs forward and bends its wings back, plunging feet-first into the water. The osprey uses strong, almost horizontal wing beats to lift itself and its prey from the water. Once airborne, the osprey rearranges the fish in its feet, carrying it with one foot in front of the other so that the fish is facing forward. This position presumably makes the fish more aerodynamic, and easier to carry. The osprey then takes the fish to a perch, often near the nest, to eat. Osprey generally eat fish beginning with the head and working toward the tail. A male who is also providing food for a mate and offspring during the breeding season will typically consume at least part of the fish before delivering the remainder to the female. Ospreys do not cache fish. If a fish is larger than an osprey (and his mate and offspring if breeding) can consume, the fish is discarded, carried around with the osprey, or left in the nest. Ospreys do not generally need to drink water. Fish flesh supplies sufficient amounts of water to meet their requirements.
Ospreys catch fish on 24 to 74% of their dives. This success rate is affected by individual ability, weather and tide. Some studies have shown that ospreys are most successful hunting at midtide and when the weather is calm.
Though the vast majority of osprey prey items are live fish, ospreys have been observed to eat other foods on occasion. These include birds, snakes, voles, squirrels, muskrats (Ondatra zibethicus), salamanders, conchs, and even a small alligator (Alligator mississippiensis). Reports of ospreys feeding on carrion are rare. However, they have been observed eating dead white-tailed deer (Odocoileus virginianus) and opossum (Didelphis virginiana).
Animal Foods: birds; mammals; amphibians; reptiles; fish; carrion ; mollusks
Primary Diet: carnivore (Piscivore )
Ospreys are vulnerable to predation from aerial predators, such as owls and eagles . In North America, Bald eagles and great horned owls are known predators of osprey nestlings and (occasionally) adults. The speckled appearance of osprey chicks camouflages them in the nest and may be an adaptation to minimize predation by diurnal avian predators like the bald eagle.
Raccoons, snakes and other climbing animals are suspected predators of osprey eggs and nestlings. Selection by such terrestrial predators may explain why the majority of osprey nests in many area, for example in the Chesapeake Bay region of the U.S., are built over water. Crocodilians may prey on wintering ospreys. Nile crocodiles (Crocodylus niloticus) sometimes kill ospreys bathing and roosting near water in Africa.
Known Predators:
Anti-predator Adaptations: cryptic
While ospreys provide food for some species (see Predation), it is unlikely that they represent a significant portion of the diet of any species. Ospreys do prey on fish, and are likely have some effect on local fish populations. Like most predators, ospreys are host to many different species of parasites, including feather mites. They are not parasitic or mutualistic with any other species.
Ospreys nests are used by many species of birds other than ospreys. Smaller cavity-nesting species, such as common grackles, tree swallows, barn swallows, European starlings and house sparrows build nests within osprey nests. Other larger species will usurp osprey nests for their own use in the spring before the resident ospreys return. In North America, these species include great blue herons, Canada geese, bald eagles, Red-tailed hawks, Great horned owls, herring gulls and common ravens.
Ospreys in some areas, particularly boreal and other northern forested regions, may have historically been dependant on beavers for creation of habitat. Beavers create osprey habitat by building dams, which create shallow ponds for fishing and dead trees appropriate for building nests.
Ospreys may be a valuable indicator species for monitoring the long-term health of large rivers, bays and estuaries. Ospreys are well-suited to this role because of their piscivorous lifestyle and their known sensitivity to many contaminants. They are also relatively easily studied because they have conspicuous nests and are tolerant of short-term disturbance such as nest observations by researchers. The presence of ospreys may also benefit local economies by boosting ecotourism.
Positive Impacts: ecotourism
There are no known negative impacts of ospreys on humans. In the past, some fishermen have believed that ospreys competed with them for fish. However, studies have demonstrated that ospreys take a very small portion of all fish harvested and are not serious competition for commercial and recreational fishing.
Ospreys are not listed under the Endangered Species Act. However, this species is listed as threatened, endangered or a species of special concern in several U.S. states, including Michigan. Ospreys are also protected under the U.S. Migratory Bird Act and CITES Appendix II. They are not listed on the IUCN Red List.
In the late 19th and early 20th centuries, the main threats to osprey populations were egg collectors and shootings. These declined by the mid-twentieth century, though some shootings still occur. With the introduction and widespread use of the pesticide DDT (dichloro-diphenyl-trichloroethane), osprey populations in many areas declined sharply from the 1950’s through the 1970’s. During this period, 90% of breeding pairs disappeared from the Atlantic coast between New York City and Boston. DDT was banned in the U.S. around 1970, but continues to be used in some countries that serve as wintering grounds for ospreys. Populations of ospreys largely rebounded after the banning of DDT and are now reaching historic levels. Installation of artificial nest structures, hacking projects and new habitat created by reservoirs have allowed osprey populations to increase and expand their range.
US Migratory Bird Act: protected
US Federal List: no special status
CITES: appendix ii
State of Michigan List: threatened
IUCN Red List of Threatened Species: least concern
Ospreys use several different vocalizations to communicate with one another. Up to five different calls have been recognized by researchers. These calls are nearly always associated with a visual display, such as a characteristic flight or posture. Vocalizations are used for begging, alarm, courtship, and nest defense. One notable display is the “sky-dance,” which is an elaborate aerial display performed by males during courtship and early incubation. During this display, a male carrying a fish or nest material gives a screaming call while simultaneously performing short undulating flights separated by periods of hovering. Alarm calls are often given when a potential predator or disturbance such as a boat or human approaches the nest. These calls are usually accompanied by erect posturing and diving flight.
Communication Channels: visual ; tactile ; acoustic
Perception Channels: visual ; tactile ; acoustic ; chemical
Bones belonging to earlier Pandion species from the mid- to late-Miocene (approx. 13 million years ago) were found in California and Florida. These prehistoric osprey species were slightly less robust than modern ospreys, but otherwise very similar.
Some ospreys migrate seasonally, but not all. Non-migratory populations breed and winter in the same location, though they may wander several hours from their nest during the non-breeding season. These populations begin breeding between December and March. Migratory populations generally breed where winters are cold enough to drive fish into deep water where they are inaccessible. These populations begin breeding in April or May.
Courtship in ospreys centers on food and nest sites. In migratory osprey populations, males and females arrive at the nest site separately, the male often arriving several days earlier than the female. Male ospreys sometimes perform a conspicuous aerial display near the nest site. This display usually occurs during early courtship, and may serve to attract potential mates or to threaten an intruder. Both sexes collect materials for the nest, but the female does most of the arranging of materials at the nest. Osprey nests are typically constructed of sticks, and lined with softer materials such as seaweed, kelp, grasses or cardboard. A wide variety of flotsam and jetsam may also be incorporated into osprey nests, including fishing line, plastic bags and nearly anything else that an osprey might find and can lift. Osprey pairs use the same nest year after year, but must spend some time each year repairing it and adding materials before eggs can be laid.
Once a pair has established a nest, the male begins to deliver food to the female. This feeding continues until the young fledge or the nest fails. Generally, females that receive more food are more receptive to mating attempts by the male, and are less likely to copulate with other males. Females beg for food from their mates, and occasionally from neighboring males if they are not well fed by their mate. Males may protect their paternity by feeding their mate. They may also protect their paternity by guarding their mate from other males and copulating frequently when she is most fertile (several days before egg laying).
Ospreys are generally monogamous. However, polygyny can occur in rare instances where nest sites are close enough together that a male can defend two nests. When this occurs, the first nest usually experiences higher reproductive success than the second because the male devotes more resources to that nest.
Mating System: monogamous ; polygynous
The breeding season of ospreys differs between populations. Non-migratory populations breed in the winter and spring, laying eggs between December and March. The breeding season of migratory populations occurs in the spring and summer, with egg laying in April and May. Two to four eggs are laid over a period of several days, each 1 to 2 days apart. Both the male and female incubate the eggs, which hatch after approximately 40 days. Because incubation starts when the first egg is laid, the eggs hatch asynchronously in the order in which they were laid. Chicks that hatch first are larger and have a competitive advantage over those that are hatch later. If food becomes scarce, the smaller chicks are less successful in competing for food, and often die. This decrease in the number of chicks in the nest makes food more available to the surviving chicks, and increases their likelihood of survival. This process, common in raptors, is called brood reduction.
When osprey chicks hatch, they are covered in white down with brown streaks on the face, back, and wings. This is replaced by charcoal-colored down after approximately 10 days. Feathers begin to replace the down at approximately two weeks. By one month after hatching, chicks have reached 70 to 80% of the adult size. Osprey chicks fledge between 48 and 76 days old. Generally, chicks in migratory populations fledge sooner than those in non-migratory populations. After fledging, young ospreys begin to hunt on their own. However, they often continue to return to the nest to receive food from their parents for two to eight weeks after fledging. Because ospreys migrate individually, juvenile ospreys must be fully independent of their parents by the time the southward migration begins.
Ospreys are sexually mature at approximately 3 years old, but may not breed until age 5 in areas where nest sites are scarce. Migratory ospreys in both Europe and the U.S. exhibit a pattern of behavior that is unusual in raptors. Rather than returning to the breeding grounds in their first summer, yearling ospreys almost always remain on the wintering grounds throughout the year. They then return to the breeding grounds the following summer when they are more likely to be able to breed successfully. This strategy allows young ospreys that are too physically immature to breed to avoid an unnecessary migration.
Breeding interval: Ospreys breed once yearly.
Breeding season: The breeding season lasts for approximately 2.5 to 4 months. Breeding begins between December and March in non-migratory populations. In migratory populations, breeding begins in April or May.
Range eggs per season: 1 to 7.
Average eggs per season: 3.
Range time to hatching: 32 to 43 days.
Range fledging age: 48 to 59 days.
Range time to independence: 7 to 17 weeks.
Average age at sexual or reproductive maturity (female): 3 years.
Average age at sexual or reproductive maturity (male): 3 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; oviparous
Average eggs per season: 3.
Average age at sexual or reproductive maturity (male)
Sex: male: 1095 days.
Average age at sexual or reproductive maturity (female)
Sex: female: 1095 days.
Both male and female ospreys care for their young. Ospreys provide parental care by protecting their young from from predators and weather, and by feeding them. During incubation and the nestling stage, the male osprey provides food to the female and the chicks. This entails delivering 60 to 100 g of fish to the nest per daylight hour (3 to 10 fish per day) during the nestling and fledgling stages. When a fish is delivered to the nest, one of the adults rips pieces of flesh from the fish and feeds them to the chicks. Parents continue to feed the young until two to eight weeks after they fledge.
During the first weeks after hatching, osprey chicks are not able to control their body temperature well. The female parent broods the chicks almost constantly for the first two weeks. She continues to brood them intermittently during very hot or cool weather until they are approximately four weeks old. Both parents expend considerable effort protecting the nest from intruders, including other ospreys and potential predators.
Parental Investment: no parental involvement; altricial ; pre-hatching/birth (Provisioning: Male, Protecting: Male, Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female); pre-independence (Provisioning: Male, Female, Protecting: Male, Female)
Resident breeder.
The osprey (Pandion haliaetus), /ˈɒspri, -preɪ/,[2] also called 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 60 cm (24 in) in length and 180 cm (71 in) across the wings. It is brown on the upperparts and predominantly greyish on the head and underparts.
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 possesses specialised physical characteristics and unique behaviour in hunting its prey. Its unique characteristics classify it in its own taxonomic genus, Pandion, and family, Pandionidae.
The osprey was described by Carl Linnaeus under the name Falco haliaeetus in his landmark 1758 10th edition of Systema Naturae.[3] The genus, Pandion, is the sole member of the family Pandionidae, and used to contain only one species, the osprey (P. haliaetus). The genus Pandion was described by the French zoologist Marie Jules César Savigny in 1809.[4][5] It has always presented something of a riddle to taxonomists, but here it is treated as the sole living member of the family Pandionidae, and the family listed in its traditional place as part of the order Accipitriformes.
Other schemes place it alongside the hawks and eagles in the family Accipitridae. The Sibley-Ahlquist taxonomy has placed it together with the other diurnal raptors in a greatly enlarged Ciconiiformes, but this results in an unnatural paraphyletic classification.[6]
The osprey is unusual in that it is a single living species that occurs nearly worldwide. Even the few subspecies are not unequivocally separable. There are four generally recognised subspecies, although differences are small, and ITIS lists only the first three.[4]
To date there have been two extinct species named from the fossil record.[11] Pandion homalopteron was named by Stuart L. Warter in 1976 from fossils of Middle Miocene, Barstovian age, found in marine deposits in the southern part of California. The second named species Pandion lovensis, was described in 1985 by Jonathan J. Becker from fossils found in Florida and dating to the latest Clarendonian and possibly representing a separate lineage from that of P. homalopteron and P. haliaetus. A number of claw fossils have been recovered from Pliocene and Pleistocene sediments in Florida and South Carolina.
The oldest recognized family Pandionidae fossils have been recovered from the Oligocene age Jebel Qatrani Formation, of Faiyum, Egypt. However, they are not complete enough to assign to a specific genus.[12] Another Pandionidae claw fossil was recovered from Early Oligocene deposits in the Mainz basin, Germany, and was described in 2006 by Gerald Mayr.[13]
The genus name Pandion derives from Pandíōn Πανδίων, the mythical Greek king of Athens and grandfather of Theseus, Pandion II. The species name haliaetus (Latin: haliaeetus)[14] comes from Greek ἁλιάετος haliáetos "sea-eagle" (also ἁλιαίετος haliaietos) from the combining form ἁλι- hali- of ἅλς hals "sea" and ἀετός aetos, "eagle".[15][16]
The origins of osprey are obscure;[17] the word itself was first recorded around 1460, derived via the Anglo-French ospriet and the Medieval Latin avis prede "bird of prey," from the Latin avis praedae though the Oxford English Dictionary notes a connection with the Latin ossifraga or "bone breaker" of Pliny the Elder.[18][19] However, this term referred to the bearded vulture.[20]
The osprey differs in several respects from other diurnal birds of prey. Its toes are of equal length, its tarsi are reticulate, and its talons are rounded, rather than grooved. The osprey and owls are the only raptors whose outer toe is reversible, allowing them to grasp their prey with two toes in front and two behind. This is particularly helpful when they grab slippery fish.[21] The osprey is 0.9–2.1 kg (2.0–4.6 lb) in weight and 50–66 cm (20–26 in) in length with a 127–180 cm (50–71 in) wingspan. It is, thus, of similar size to the largest members of the Buteo or Falco genera. The subspecies are fairly close in size, with the nominate subspecies averaging 1.53 kg (3.4 lb), P. h. carolinensis averaging 1.7 kg (3.7 lb) and P. h. cristatus averaging 1.25 kg (2.8 lb). The wing chord measures 38 to 52 cm (15 to 20 in), the tail measures 16.5 to 24 cm (6.5 to 9.4 in) and the tarsus is 5.2–6.6 cm (2.0–2.6 in).[22][23]
The upperparts are a deep, glossy brown, while the breast is white, 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.[24] The irises of the eyes are golden to brown, and the transparent nictitating membrane is pale blue. The bill is black, with a blue cere, and the feet are white with black talons.[21] On the underside of the wings the wrists are black, which serves as a field mark.[25] A short tail and long, narrow wings with four long, finger-like feathers, and a shorter fifth, give it a very distinctive appearance.[26]
The sexes appear fairly similar, but the adult male can be distinguished from the female by its slimmer body and narrower wings. The breast band of the male is also weaker than that of the female, or is non-existent, and the underwing coverts of the male are more uniformly pale. It is straightforward to determine the sex in a breeding pair, but harder with individual birds.[26]
The 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.[24]
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. If disturbed by activity near the nest, the call is a frenzied cheereek![27]
The osprey is the second most widely distributed raptor species, after the peregrine falcon, and is one of only six land-birds with a worldwide distribution.[28] 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.[29] It is found in summer throughout Europe north into Ireland, Scandinavia, Finland and Great Britain though not Iceland, and winters in North Africa.[30] In Australia it is mainly sedentary and found patchily around the coastline, though it is a non-breeding visitor to eastern Victoria and Tasmania.[31]
There is a 1,000 km (620 mi) 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.[32] 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.[33] 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,[34] and Southeast Asia from Myanmar through to Indochina and southern China, Indonesia, Malaysia and the Philippines.[35]
The osprey is piscivorous, with fish making up 99% of its diet.[36] It typically takes live fish weighing 150–300 g (5.3–10.6 oz) and about 25–35 cm (9.8–13.8 in) in length, but virtually any type of fish from 50 g (1.8 oz) to 2 kg (4.4 lb) can be taken.[22] Even larger 2.8 kg (6.2 lb) northern pike (Esox lucius) has been taken in Russia.[37] The species rarely scavenges dead or dying fish.[38]
Ospreys have vision that is well adapted to detecting underwater objects from the air. Prey is first sighted when the osprey is 10–40 m (33–131 ft) above the water, after which the bird hovers momentarily and then plunges feet first into the water.[39] They catch fish by diving into a body of water, oftentimes completely submerging their entire bodies. As an osprey dives it adjusts the angle of its flight to account for the distortion of the fish's image caused by refraction. Ospreys will typically eat on a nearby perch but have also been known to carry fish for longer distances.[40]
Occasionally, the osprey may prey on rodents, rabbits, hares, other mammals, snakes, turtles, frogs, birds, salamanders, conchs and crustaceans.[41][42][43] Reports of ospreys feeding on carrion are rare. They have been observed eating dead white-tailed deer and Virginia opossum.[44]
The osprey has several adaptations that suit its piscivorous lifestyle:
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 there are 14 or so similar nesting sites 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.[36][47] As wide as 2 meters and weighing about 135 kg (298 lb), large nests on utility poles may be fire hazards and have caused power outages.[48]
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 there may be a shortage of suitable tall structures. If there are no nesting sites 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.[49] In some regions ospreys prefer transmission towers as nesting sites, e.g. in eastern Germany.[50]
The nesting platform design developed by one organization, Citizens United to Protect the Maurice River and Its Tributaries, Inc. has become the official design of the State of New Jersey, U.S. The nesting platform plans and materials list, available online, have been utilized by people from a number of different geographical regions.[51] Osprey-watch.org is the global site for mapping osprey nest locations and logging observations on reproductive success.[52]
Ospreys usually mate for life. Rarely, polyandry has been recorded.[53] The breeding season varies according to latitude; spring (September–October) in southern Australia, April to July in northern Australia and winter (June–August) in southern Queensland.[47] In spring the pair begins a five-month period of partnership to raise their young. The female lays two to four eggs within a month, and relies on the size of the nest to conserve heat. The eggs are whitish with bold splotches of reddish-brown and are about 6.2 cm × 4.5 cm (2.4 in × 1.8 in) and weigh about 65 g (2.3 oz).[47] The eggs are incubated for about 35–43 days to hatching.[54]
The newly hatched chicks weigh only 50–60 g (1.8–2.1 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.[53] When food is scarce, the first chicks to hatch are most likely to survive. The typical lifespan is 7–10 years, though rarely individuals can grow to as old as 20–25 years.
The oldest European wild osprey on record lived to be over thirty years of age. In North America, great horned owls (Bubo virginianus), golden eagles (Aquila chrysaetos), and bald eagles (Haliaeetus leucocephalus) are the only major predators of ospreys, capable of taking both nestlings and adults.[55][56][57][58][59] However, kleptoparasitism by bald eagles, where the larger raptor steals the osprey's catch, is more common than predation. The white-tailed eagle (Haliaeetus albicilla), which is very similar to the bald eagle, may harass or prey on the osprey in Eurasia.[60] Raccoons (Procyon lotor) can be a serious threat to nestlings or eggs if they can access the nest.[61] Endoparasitic trematodes (Scaphanocephalus expansus and Neodiplostomum spp.) have been recorded in wild ospreys.[62]
European breeders winter in Africa.[63] American and Canadian breeders winter in South America, although some stay in the southernmost U.S. states such as Florida and California.[64] Some ospreys from Florida migrate to South America.[65] Australasian ospreys tend not to migrate.
Studies of Swedish ospreys showed that females tend to migrate to Africa earlier than 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 during the day, they sometimes fly in the dark hours particularly in crossings over water and cover on average 260–280 km (160–170 mi) per day with a maximum of 431 km (268 mi) per day.[66] European birds may also winter in South Asia, as indicated by an osprey tagged in Norway being monitored in western India.[67] In the Mediterranean, ospreys show partial migratory behaviour with some individuals remaining resident, whilst others undertake relatively short migration trips.[68]
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.[69] These deaths can also be categorized into spatial patterns: Spring mortality occurs mainly in Africa, which can be traced to crossing the Sahara desert. Mortality can also occur through mishaps with human utilities, such as nesting near overhead electric cables or collisions with aircraft.[70]
The osprey has a large range, covering 9,670,000 km2 (3,730,000 sq mi) 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.[71] There is evidence for regional decline in South Australia where former territories at locations in the Spencer Gulf and along the lower Murray River have been vacant for decades.[32]
In the late 19th and early 20th centuries, the main threats to osprey populations were egg collectors and hunting of the adults along with other birds of prey,[55][72] but osprey populations declined drastically in many areas in the 1950s and 1960s; this appeared to be in part due to the toxic effects of insecticides such as DDT on reproduction.[73] The pesticide interfered with the bird's calcium metabolism which resulted in thin-shelled, easily broken or infertile eggs.[29] Possibly because of the banning of DDT in many countries in the early 1970s, together with reduced persecution, the osprey, as well as other affected bird of prey species, have made significant recoveries.[36] In South Australia, nesting sites on the Eyre Peninsula and Kangaroo Island are vulnerable to unmanaged coastal recreation and encroaching urban development.[32]
I think he'll be to Rome
As is the osprey to the fish, who takes it
By sovereignty of nature.
In Buddhism, the osprey is sometimes represented as the "King of Birds", especially in 'The Jātaka: Or, Stories of the Buddha’s Former Births' , no. 486.
The osprey is used as a brand name for various products and sports teams, such as the Ospreys (a Welsh Rugby team) and Seattle Seahawks (an American football team of the National Football League). The official mascot of athletic teams at the University of North Carolina Wilmington is named Sammy C. Hawk. The Riverhawk is the mascot for Northeastern State University in Tahlequah, Oklahoma as well as the University of Massachusetts-Lowell. The Osprey is the mascot of the University of North Florida in Jacksonville, Florida.
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.[80]
During the 2017 regular session of the Oregon Legislature, there was a short-lived controversy over the western meadowlark's status as state bird versus the osprey. The sometimes-spirited debate included state representative Rich Vial playing the meadowlark's song on his smartphone over the House microphone.[81] A compromise was reached in SCR 18,[82] 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.
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(help) The osprey (Pandion haliaetus), /ˈɒspri, -preɪ/, also called 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 60 cm (24 in) in length and 180 cm (71 in) across the wings. It is brown on the upperparts and predominantly greyish on the head and underparts.
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 possesses specialised physical characteristics and unique behaviour in hunting its prey. Its unique characteristics classify it in its own taxonomic genus, Pandion, and family, Pandionidae.