Eastern osprey | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Accipitriformes |
Family: | Pandionidae |
Genus: | Pandion |
Species: | |
Subspecies: | P. h. cristatus |
Trinomial name | |
Pandion haliaetus cristatus (Vieillot, 1816) | |
Synonyms | |
Pandion cristatus |
The eastern osprey (Pandion haliaetus cristatus) is a diurnal, fish-eating bird of prey. They live in Oceania at coastal regions of the Australian continent, the Indonesian islands, New Guinea, and the Philippines. It is usually sedentary and pairs breed at the same nest site, building up a substantial structure on dead trees or limbs. The subspecies resides in a habitat close to coasts and estuaries that provide opportunities for fishing. In 2022, it was considered a defunct species by the IOC, due to its low genetic divergences and absence in morphological differences. [1] The eastern osprey's diet consists mostly of vertebrate fish species. It possesses specialised physical characteristics and exhibits unique behaviour to assist in hunting and catching prey.
A description as species Buteo cristatus was published in 1816 by the French ornithologist Louis Vieillot, [2] which came to be cited as a subspecies or race of a widely distributed species. [3] The epithet cristatus is derived from the Latin for 'crested' in reference to the stiff tuft of feathers that extend from the nape. [4] The subspecific treatment Pandion haliaetus cristatus distinguishes the crest from other subspecies of P. haliaetus, the name taken from ancient Greek haliaietos for 'sea eagle'. [4]
Later authors described the regional population as separate species—Pandion leucocephalus Gould, J. 1838 and Pandion gouldi Kaup, J.J. 1847—or as subspecies—Pandion haliaetus australis Burmeister, K.H.K. 1850 and Pandion haliaetus melvillensis Mathews, G.M. 1912. [5]
Gould's description identified several characteristics that distinguished his new species from widespread Pandion haliaetus, based on specimens collected in Tasmania, Rottnest Island in the west, and Port Essington; the accompanying lithograph illustrating the species—published in the Synopsis (1838) [6] to Birds of Australia —was executed by Elizabeth Gould. [4]
Some authorities maintain a treatment of the "eastern osprey" population as one of four subspecies of Pandion haliaetus , the only extant species of the genus and family. When specimens and observations of new populations were published in the nineteenth century, many authors described these as new species, revisions around the beginning of the twenty first century began to suggest that status as a full species was warranted. [7]
The Australian Faunal Directory recognises a full species treatment, [5] citing a 2008 revision that noted genetic distance comparable to closely related species of Hieraeetus and Aquila (Wink, et al., 2004) [7] and minor but consistent distinctions in morphology and plumage colour. [8] Behavioural differences between the three contentious populations include this species residence at marine habitat, whereas the North American population is found breeding and colonising sites near freshwater. [9]
Pandion , described by the French zoologist Marie Jules César Savigny in 1809, [10] is the sole genus of the family Pandionidae; it is named for a mythic Greek figure known as Pandion. Some arrangements 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 allied 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 results in an unnatural paraphyletic classification. [11]
They are known by the common name osprey, or distinguished as the eastern osprey, [5] other names include fish hawk and white-headed osprey. [3] [5] Gould noted the informal vernacular used after settlement of Australia, the 'Little Fish-Hawk' in New South Wales and 'Fish-Hawk' recorded at the Swan River Colony by John Gilbert; the extant names for the species were Joor-jout at Port Essington and another in southwest Australia, transliterated from the Nyungar language; [12] this latter name has proposed for common use in southwest Australia as yoondoordo [pronounced yoon’door’daw]. [13]
Pandion cristatus, comparable in size as a medium-sized raptor or large hawk, occurs near the coast and large water bodies and is highly adapted to hunt and capture marine animals. [14] [15] The plumage is dark brown on the upper surfaces, and pale at the head and lower parts. The throat is white, a black line extends from this through the eye to a dark patch around the ear, demarcating this from the pale colour at the head. When not in flight, the feathers at the crown form a small crest. The breast is dappled with brownish patches, lacing below the neck, this is darker and more strongly banded in the female. The female of the species also tends to be larger. [14] The wing measurements of the females range from 410 to 478 millimetres, males are 391 to 470 mm. The weight of the female is 1.2 to 1.6 kilograms, males are 0.9 to 1.2 kg. The size range of the black bill is 29 to 35 millimetres, [15] and the upper mandible is acutely hooked. The legs and feet of the species are strong and a light grey or white colour. [14] [16] The pattern of the scales at the tarsus is reticulate. [9] The irides are yellow. The juveniles resemble adults, although the iris colour is a darker orange-yellow and plumage is distinguishable in multiple and subtle ways. [16] In flight, the eastern osprey has bowed wings with narrow primary feathers that are angled and separate, giving a fingered appearance to the observer below. The eyes are set toward the front of the head, which along with the neck is proportionally small. The species swivels and cranes its neck while observing its surroundings in a curious and characteristic manner. The osprey resembles the white-bellied sea eagle Haliaeetus leucogaster , which has similar habitat and range, although the adult size is only that of the larger species' juvenile; the wings of an osprey are sharply angled rather than the up-swept outline of the soaring eagle. [14]
Ospreys differ in several respects from other diurnal birds of prey, toes are of equal length, its tarsi are reticulate, and its talons are rounded, rather than grooved. The eastern and western osprey ( Pandion ) and owls (Strigiformes) are the only hunters 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 grasp slippery fish. [17]
The states and territories of Australia where the species is recorded as occurring are Western Australia, the Northern Territory, Queensland, New South Wales, [18] South Australia and Tasmania, [5] The range is a narrow strip at the coast and offshore islands, although it is occasionally found at open river systems and beyond tidal plains. [3] Visits to inland regions from the north during the wet season may occur in years of heavier rainfall. [9] On this continent it is mainly sedentary, non-migratory, in contrast to the other subspecific populations of Pandion haliaetus. They occur patchily around the coastline, although it is a non-breeding visitor to eastern Victoria and Tasmania. [19] 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 at the southwest of Australia. [20] The species had been reported as uncommon in the southeast of Australia. [21]
Other regions inhabited by the species at the Philippines, Indonesia and New Guinea. [14] Seasonal visitors to Sulawesi arrive from the south, and these are presumed to have migrated from the north of Australia. [16]
The tree selected as a roost or nest site in Australia is a large eucalypt. They may be seen in flight over a variety of habitats occurring between their residence and hunting waters. [16]
The species is solitary or paired with a breeding partner, the association of several individuals in family groups are unusual records. They are a diurnal species, ranging out from a nest or perch over water bodies during daylight, but have been recorded hunting at night. [16] Their flight may be high, soaring over and surveying the water, or quartering closer to the surface; some flight is seemingly unrelated to hunting.
The diet is largely local species of fish, although a favoured target in Australia is known to be mullet when available. [16] Occasional records are given for other marine life—sea snakes, molluscs and crustaceans—and for terrestrial species of reptiles, insects, birds and mammals. [16] [22] They are known to capture sea birds in flight. [16] [9]
Ospreys have vision that is well adapted to detecting underwater objects from the air. Prey is first sighted when the eastern osprey is 10 to 40 metres above the water, after which the bird hovers momentarily then plunges feet first with wings raised; a large splash is made as it enters the water. [23] [9] The descent toward their prey may be done in stages, and they may immerse themselves up to a depth of 1 metre. After seizing their target they use heavy wing beats to rise from the water's surface, resuming a regular action with the fish being carried head first toward the shore. [16] The prey is "slung torpedo-fashion" with a leading foot behind the head and the other clasping behind, this aligning habit distinguishes Pandion from indifferent clutching of prey by fishing eagles. [9] Their large prey is not swallowed immediately, instead being butchered at a perch or nest site outside the breeding season. [14]
The genus Pandion has several adaptations that suit its piscivorous lifestyle, these include reversible outer toes, sharp spicules on the underside of the toes, [24] closable nostrils to keep out water during dives, and backwards-facing scales on the talons which act as barbs to help hold its catch. The osprey has dense plumage which is oily and prevents its feathers from getting waterlogged. [25]
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 that is usually built in the fork of a dead tree or limb, cliff faces are also utilised. [14] trees, rocky outcrops, utility poles, artificial platforms or offshore islets. [26] [27] Continually occupied nest structures may reach up to two metres in height. [14] Nests can be as wide as 2 meters [14] and weighing about 135 kg.[ citation needed ]
Generally, eastern ospreys reach sexual maturity and begin breeding around the age of three to four years.
Eastern ospreys usually mate for life, although polyandry has been recorded in several instances. [28] The breeding period varies according to local seasons: this begins between September and October in southern Australia, April to July in northern Australia and June–August in southern Queensland. [27] In spring the pair begins a five-month period of partnership to raise their young. The clutch size is usually two to three eggs, sometimes up to four, and are able to brood twice in a season. [16] These are laid within a month, and relies on the size of the nest to conserve heat. The egg shell is white or buff with bold splotches and spots of reddish-brown, sometimes so dark as to be black; purple or grey blotches may appear beneath the surface of the shell. [12] [16] The egg measurements are about 62 x 45 millimetres and weigh about 65 grams. [27] The eggs are incubated for about 35–43 days to hatching. [29]
The newly hatched chicks weigh 50 to 60 grams and fledge in 8 to 10 weeks. A study on Kangaroo Island 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. [28] 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.
A nest examined in 1902 found fish skeletons at the edge and a seaside plant "pig-face" ( Mesembryanthemum ) in full growth. [30]
The species is listed as vulnerable in South Australia, under the National Parks and Wildlife Act 1972 [31] There is evidence for regional decline in the state, where former territories at locations in the Spencer Gulf and along the lower Murray River have been vacant for decades. Nesting sites on the Eyre Peninsula and Kangaroo Island are vulnerable to unmanaged coastal recreation and encroaching urban development. [20] As of 2023 [update] there were estimated to be only 50 breeding pairs left in SA, mostly on islands and isolated stretches of coast. After finding that foxes had been stealing eggs, the Friends of Osprey conservation group and National Parks and Wildlife Service South Australia installed towers to provide an elevated platform for ospreys to nest. Their efforts were rewarded on Tumby Island, where a chick hatched in October 2023. [32]
In New South Wales, the osprey is listed as vulnerable under the Biodiversity Conservation Act 2016 (NSW) . [31] For this reason, conservationists cannot move a nest of ospreys from the bottom left light tower of Central Coast Stadium.[ when? ][ citation needed ]
As of October 2023 [update] , the bird is not listed or protected by legislation in other states. [31]
In Western Australia, it is relatively common in the north and less frequently recorded in the south.[ citation needed ] A 1902 report by Alexander Milligan of a breeding pair in the southwest region was published in The Emu , and a description of a nest with two eggs located at Cape Mentelle which had been photographed eleven years earlier by A. J. Campbell. One egg was taken for deposit at the state's museum by Milligan and along with the museum's director, B. H. Woodward, charged the warden of the cave system with protection of the site. [30]
The species is rare in Victoria and now absent from Tasmania. [9]
The osprey, 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 white-bellied sea eagle, also known as the white-breasted sea eagle, is a large diurnal bird of prey in the family Accipitridae. Originally described by Johann Friedrich Gmelin in 1788, it is closely related to Sanford's sea eagle of the Solomon Islands, and the two are considered a superspecies. A distinctive bird, the adult white-bellied sea eagle has a white head, breast, under-wing coverts and tail. The upper parts are grey and the black under-wing flight feathers contrast with the white coverts. The tail is short and wedge-shaped as in all Haliaeetinae species. Like many raptors, the female is larger than the male, and can measure up to 90 cm (35 in) long with a wingspan of up to 2.2 m (7.2 ft), and weigh 4.5 kg (9.9 lb). Immature birds have brown plumage, which is gradually replaced by white until the age of five or six years. The call is a loud goose-like honking.
The grey currawong is a large passerine bird native to southern Australia, including Tasmania. One of three currawong species in the genus Strepera, it is closely related to the butcherbirds and Australian magpie of the family Artamidae. It is a large crow-like bird, around 48 cm (19 in) long on average; with yellow irises, a heavy bill, dark plumage with white undertail and wing patches. The male and female are similar in appearance. Six subspecies are recognised and are distinguished by overall plumage colour, which ranges from slate-grey for the nominate from New South Wales and eastern Victoria and subspecies plumbea from Western Australia, to sooty black for the clinking currawong of Tasmania and subspecies halmaturina from Kangaroo Island. All grey currawongs have a loud distinctive ringing or clinking call.
The pied currawong is a black passerine bird native to eastern Australia and Lord Howe Island. One of three currawong species in the genus Strepera, it is closely related to the butcherbirds and Australian magpie of the family Artamidae. Six subspecies are recognised. It is a robust crowlike bird averaging around 48 cm (19 in) in length, black or sooty grey-black in plumage with white undertail and wing patches, yellow irises, and a heavy bill. The male and female are similar in appearance. Known for its melodious calls, the species' name currawong is believed to be of indigenous origin.
The black-shouldered kite, also known as the Australian black-shouldered kite, is a small raptor found in open habitats throughout Australia. It resembles similar species found in Africa, Eurasia and North America, including the black-winged kite, a species that has in the past also been called "black-shouldered kite". Measuring around 35 cm (14 in) in length, with a wingspan of 80–100 cm (31–39 in), the adult black-shouldered kite has predominantly grey-white plumage and prominent black markings above its red eyes. It gains its name from the black patches on its wings. The primary call is a clear whistle, uttered in flight and while hovering. It can be confused with the related letter-winged kite in Australia, which is distinguished by the striking black markings under its wings.
The sittellas are a family, Neosittidae, of small passerine birds found only in Australasia. They resemble nuthatches, but whilst they were considered to be in that family for many years they are now afforded their own family. They do not migrate other than for local movements.
The greater crested tern, also called crested tern or swift tern, is a tern in the family Laridae that nests in dense colonies on coastlines and islands in the tropical and subtropical Old World. Its five subspecies breed in the area from South Africa around the Indian Ocean to the central Pacific and Australia, all populations dispersing widely from the breeding range after nesting. This large tern is closely related to the royal and lesser crested terns, but can be distinguished by its size and bill colour.
The red-tailed tropicbird is a seabird native to tropical parts of the Indian and Pacific Oceans. One of three closely related species of tropicbird (Phaethontidae), it was described by Pieter Boddaert in 1783. Superficially resembling a tern in appearance, it has almost all-white plumage with a black mask and a red bill. The sexes have similar plumage. As referenced in the common name, adults have red tail streamers that are about twice their body length. Four subspecies are recognised, but there is evidence of clinal variation in body size—with smaller birds in the north and larger in the south—and hence no grounds for subspecies.
The masked booby, also called the masked gannet or the blue-faced booby, is a large seabird of the booby and gannet family, Sulidae. First described by the French naturalist René-Primevère Lesson in 1831, the masked booby is one of six species of booby in the genus Sula. It has a typical sulid body shape, with a long pointed yellowish bill, long neck, aerodynamic body, long slender wings and pointed tail. The adult is bright white with black wings, a black tail and a dark face mask; at 75–85 cm (30–33 in) long, it is the largest species of booby. The sexes have similar plumage. This species ranges across tropical oceans, except in the eastern Atlantic and eastern Pacific. In the latter, it is replaced by the Nazca booby, which was formerly regarded as a subspecies of masked booby.
The yellow-billed spoonbill is a gregarious wading bird of the ibis and spoonbill family, Threskiornithidae. It is native to Australia, and is a vagrant to New Zealand, Lord Howe Island and Norfolk Island.
The white-plumed honeyeater is a small passerine bird endemic to Australia. White-plumed honeyeaters are common around water and are often seen in backyards and suburbs with vegetation cover.
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The bristlebirds are a family of passerine birds, Dasyornithidae. There are three species in one genus, Dasyornis. The family is endemic to the south-east coast and south-west corner of Australia. The genus Dasyornis was sometimes placed in the Acanthizidae or, as a subfamily, Dasyornithinae, along with the Acanthizinae and Pardalotinae, within an expanded Pardalotidae, before being elevated to full family level by Christidis & Boles (2008).
Pandion is a genus of fish-eating bird of prey, known as ospreys, the only genus of family Pandionidae. Most taxonomic treatments have regarded this genus as containing a single living species, separated into subspecies and found worldwide near water, while some treatments recognize two living species, splitting off the eastern osprey from Australia and southeast Asia.