Steller's sea eagle

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Steller's sea eagle
Haliaeetus pelagicus (Rausu, Japan).jpg
A Steller's sea eagle near Rausu, Hokkaido, Japan
CITES Appendix II (CITES) [2]
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Accipitriformes
Family: Accipitridae
Genus: Haliaeetus
Species:
H. pelagicus
Binomial name
Haliaeetus pelagicus
(Pallas, 1811)
Haliaeetus pelagicus distr.png
  breeding only
  resident all year
  winter only
  vagrant range
Synonyms [3]
  • Aquila pelagica(Pallas, 1811)
  • Thalassaetus pelagicus(Pallas)
  • Falco leucopterus(Temminck, 1824)
  • Falco imperator(Kittlitz, 1832)

Steller's sea eagle (Haliaeetus pelagicus), also known as Pacific sea eagle or white-shouldered eagle, is a very large diurnal bird of prey in the family Accipitridae. It was described first by Peter Simon Pallas in 1811. No subspecies are recognised. A sturdy eagle, it has dark brown plumage with white wings and tail, a yellow beak, and yellow talons. Typically, it is the heaviest eagle in the world, at about 5 to 10 kg (11 to 22 lb), but in some standard measurements, may be ranked below the harpy eagle (Harpia harpyja) and the Philippine eagle (Pithecophaga jefferyi). [4] Steller's sea eagle females are bigger than males.

Contents

The Steller's sea eagle is endemic to coastal northeastern Asia, where it lives in Russia, Korea, Japan, China, and Taiwan. It mainly preys on fish and water birds. The Kamchatka Peninsula in Far Eastern Russia is known for its relatively large population of these birds; about 4,000 of these eagles live there. [5] Steller's sea eagle is listed as vulnerable on the International Union for Conservation of Nature's Red List (IUCN Red List) of threatened species.

Taxonomy

This species was described initially as Aquila pelagica by Prussian naturalist Peter Simon Pallas, in 1811. [6] The species name is the Ancient Greek pelagos, "the open sea/ocean". [7] Dutch naturalist Coenraad Jacob Temminck named it Falco leucopterus, "white winged eagle", in 1824, [8] and Heinrich von Kittlitz called it Falco imperator in 1832. [9] George Robert Gray moved the species into the genus Haliaeetus in 1849. [10]

"Steller's sea eagle" has been designated the official name by the International Ornithologists' Union (IOU). [11] It is named after the German naturalist, Georg Wilhelm Steller. [12] It also is known as Steller's fish eagle, Pacific sea eagle, or white-shouldered eagle. [4] In Russian, the eagle has been called morskoi orel (sea eagle), pestryi morskoi orel (mottled sea eagle), or beloplechii orlan (white-shouldered eagle). In Japanese, it is called ō-washi (large eagle or great eagle). [13] In Korean, the eagle is called chamsuri (true eagle). In Mandarin, it is called hǔtóu hǎidiāo (tiger-headed sea eagle).

A 1996 analysis of the cytochrome b gene of mitochondrial DNA showed that Steller's sea eagles diverged from a lineage that gave rise to the bald eagle and white-tailed eagle around 3-4 million years ago. All three of these species have yellow eyes, beaks, and talons, unlike their next-closest relative, Pallas's fish eagle. [14]

H. pelagicus is monotypic, although a dubious subspecies has been named; H. p. niger. [15] The latter name was given to the population that lacked white feathers except for the tail, and may have resided all year in Korea. Last seen in 1968 and long believed to be extinct, a female matching H. p. niger in appearance was hatched in captivity in the Bayerischen Jagdfalkenhof (Germany) in 2001 and subsequently transferred to Tierpark Berlin. Both her parents had typical coloration, indicating that H. p. niger is an extremely rare dark morph rather than a valid subspecies, as had been suggested earlier. [16] [17] One of the offspring of the dark Berlin female, a male hatched in 2014 that now lives in Skandinavisk Dyrepark (Denmark), also is a dark morph. [18]

Description

Size

A falconer holding a Steller's sea eagle in England Stellers Sea Eagle with Man.jpg
A falconer holding a Steller's sea eagle in England

Steller's sea eagle is the largest bird in the genus Haliaeetus and is one of the largest raptors overall. Females vary in weight from 6.2 to 9.5 kg (14 to 21 lb), while males are rather lighter with a weight range of 4.9 to 6.8 kg (11 to 15 lb). [4] [19] [20] The typical weight is variable, possibly due to seasonal variation in food access or general condition of eagles, but has been reported as high as a mean weight of 7.75 kg (17.1 lb) to a median estimate weight of 6.25 kg (13.8 lb), excluding expired eagles that were poisoned by lead and endured precipitous weight loss by the occasion of their deaths. [4] [19] [20] [21] [22]

At its average weight, the Steller's seems to outweigh the average harpy by around 0.5 kg (1.1 lb) and the average Philippine eagles by more than 1 kg (2.2 lb). [4] [20] [23] Steller's sea eagle can range in total length from 85 to 105 cm (2 ft 9 in to 3 ft 5 in). Apparently, males average about 89 cm (2 ft 11 in) in length, while females average about 100 cm (3 ft 3 in), marginally shorter on average than the harpy eagle and about 65 mm (2.6 in) shorter than the Philippine eagle. [4] [21]

The wingspan is from 1.95 to 2.50 m (6 ft 5 in to 8 ft 2 in) and the wing chord measurement is 560 to 680 mm (22 to 27 in). [4] [13] [24] The sea eagle's wingspan is one of the largest of any living eagle, at a median of 2.13 m (7 ft 0 in) per Ferguson-Lees (2001) or a median of 2.2 m (7 ft 3 in) per Saito (2009). [4] [21] Steller's sea eagles' absolute maximum wingspan is less certain; many sources place it at up to 2.45 m (8 ft 2 in). [25] [26] However, less substantiated records indicate that it may also reach even greater wingspans. Three separate sources claim unverified Steller's sea eagles spanning up to 2.7 m (8 ft 10 in), 2.74 m (9 ft 0 in), and 2.8 m (9 ft 2 in), respectively. If true, this would be the largest wingspan of any eagle. [27] [28] [29]

Steller's sea eagle is unique among all sea eagles in having a yellow beak even in juvenile birds, and possessing 14, not 12, rectrices. [14]

Standard measurements and physiology

Detail of head of a Steller's sea eagle in the Cincinnati Zoo, United States Steller'sSeaEagle.jpg
Detail of head of a Steller's sea eagle in the Cincinnati Zoo, United States
Close-up of feet with hooked sharp talons Riesenseeadler Fang.JPG
Close-up of feet with hooked sharp talons

As in most Haliaeetus eagles, the tarsus and tail are relatively short compared to other very large eagles at 95–100 mm (3.7–3.9 in) and 320–390 mm (13–15 in) in length, respectively, with the Philippine eagle surpassing it by up to 40 mm (1.6 in) and 110 mm (4.3 in), apparently. [4] [30] In all sea and fish eagles, the toes are relatively short and stout, with the bottom of the foot covered in spicules and the talons being relatively shorter and more strongly curved than in comparably sized eagles of forests and fields, such as the "booted eagle" group (i.e. Aquila ) or "harpy eagles". All of these specializations developed in the aid of capturing fish rather than medium-sized mammals and large birds, although, clearly these are not excluded from capture. [4] [30]

As in all fish and sea eagles, as well as the majority of the world's fish-eating raptors, Steller's sea eagle has spicules, which are bumpy waves all along the bottom of their feet, which allow them to hold fish that may otherwise slip out of their grasp. [4] The feet are very powerful despite not bearing talons as long as those of a harpy eagle. In one case, a wildlife veterinarian was badly injured when a female eagle grabbed his arm and embedded her talons, piercing through to the other side of his arm. [31]

The bill is large. The skull is around 14.6 cm (5.7 in) in total length, the culmen is from 62 to 75 mm (2.4 to 3.0 in), and the bill from the gape to the tip is around 117 mm (4.6 in). [32] [33] A Steller's sea eagle's bill is probably the largest of any living eagle, just surpassing the Philippine eagle with a sole known culmen measurement (from a mature female) of 72.2 mm (2.84 in), and are similar in robustness (if slightly shorter in culmen length) to those of the largest accipitrids, the Old World vultures. [4] [32] [34]

Plumage

Adult of the rare dark morph in Tierpark Berlin, Germany: Before the hatching of this female, which had "normal" parents, the dark morph was considered a separate subspecies. Steller's Sea Eagle in Berlin.JPG
Adult of the rare dark morph in Tierpark Berlin, Germany: Before the hatching of this female, which had "normal" parents, the dark morph was considered a separate subspecies.

Mature H. pelagicus eagles have mostly dark brown to black plumage, with strongly contrasting white on the lesser and median upper-wing coverts, under-wing coverts, thighs, under-tail coverts, and tail. Their diamond-shaped, white tails are relatively longer than those of the white-tailed eagle. [35] The bold, pied coloration of adults may play some part in social hierarchies with other eagles of their own species during the nonbreeding season, although this has not been extensively studied. [4] [30] A very rare dark morph, once regarded as a separate subspecies, H. p. niger, lacks white in its plumage, except for the tail. [16] [17] The eyes, bill, and feet of adults are yellow. [4]

The downy plumage of chicks is silky white on hatching, though it soon turns a smoky brown-grey. As in other sea eagles, remiges and rectrices of the first-year plumage are longer than those of adults. Juvenile plumage is largely a uniform dark soot-brown with occasional grey-brown streaking about the head and the neck, white feather bases, and light mottling on the rectrices. The tail of the immature eagle is white with black mottling distally. [22] [30] The young Steller's sea eagle has dark brown irises, whitish legs, and blackish-brown beak. Through at least three intermediate plumages, mottling in the tail decreases, body and wing feathering acquires a bronze cast, and the eyes and bill lighten in colour. [13] Definitive plumage is probably reached in the fourth to fifth year of life, based on data from captives. Young of the typical morph and the rare dark morph are alike. The difference only becomes clear once they have gained the adult plumage. [18]

First and intermediate plumages are difficult to distinguish from those of the white-tailed eagle, which co-occurs in the entire breeding range of H. pelagicus, but beyond their bulkier, larger overall form, they can fairly reliably be distinguished at reasonable range by their considerably more massive bill and their darker and more uniform body plumage. This is not to mention the differing shape of the Steller's diamond-shaped tail and wings (paddle-like in Steller's against the square-looking wings of the white-tailed), especially in flight, as well as a generally distinct under-wing pattern. [13]

Voice

Steller's sea eagle is known to make a deep barking cry, ra-ra-ra-raurau. In aggressive interactions, its call similar to the white-tailed eagles, but deeper. [30] During the display at the beginning of the breeding season, they have been heard to make calls to each that sound like very loud, deep-voiced gulls. [30] [36]

Distribution and habitat

Adult in the Magadan Nature Reserve, Russia, a part of the species' breeding range Beloplechii orlan - krasnoknizhnyi vid.jpg
Adult in the Magadan Nature Reserve, Russia, a part of the species' breeding range

Steller's sea eagle breeds on the Kamchatka Peninsula, the coastal area around the Sea of Okhotsk, the lower reaches of the Amur River, and on northern Sakhalin and the Shantar Islands, Russia. Many eagles migrate from breeding grounds to Korea, Japan, and China in winter. Most birds winter south of their breeding range, in the southern Kuril Islands, Russia, and Hokkaidō, Japan. Steller's sea eagle is less prone to vagrancy than the white-tailed eagle, as it lacks the long-range dispersal typical of juveniles of that species, [37] [38] but vagrant eagles have been found in North America at locations including the Pribilof Islands and Kodiak Island, as well as Texas, Nova Scotia, Massachusetts, Maine, and Newfoundland [39] (the latter five all being a single individual) [40] and inland in Asia to as far as Beijing in China and Yakutsk in Russia's Sakha Republic, and south to as far as Taiwan. [30] [41]

The large body size (see also Bergmann's rule) and distribution of Steller's sea eagle suggests it is a glacial relict, meaning it evolved in a narrow subarctic zone of the northeasternmost Asian coasts, which shifted its latitude according to ice age cycles, and never occurred anywhere else. Their nests are built on large, rocky outcroppings or at the tops of large trees on the coast and alongside large rivers with mature trees. Habitat with large Erman's birches (Betula ermanii) and floodplain forests of larches, alders, willows, and poplars are preferred. Some eagles, especially those that nest on seacoasts, may not migrate. The timing, duration, and extent of migration depends on ice conditions and food availability.

On Kamchatka, eagles overwinter in forests and river valleys near the coast, but are irregularly distributed over the peninsula. Most wintering birds there appear to be residential adults. Steller's sea eagles that do migrate fly south to winter in rivers and wetlands in Japan, but occasionally move to mountainous inland areas as opposed to the seacoast. Each winter, drifting ice on the Sea of Okhotsk drives thousands of eagles south. Ice reaches Hokkaido in late January.

Eagle numbers peak in the Nemuro Strait in late February. On Hokkaido, eagles concentrate in coastal areas and on lakes near the coast, along with substantial numbers of white-tailed eagles. Eagles depart between late March and late April, with adults typically leaving before immatures. Migrants tend to follow seacoasts and are usually observed flying singly. In groups, migrants are typically observed flying 100–200 m (330–660 ft) apart. On Kamchatka, most migrants are birds in transitional plumages. They are also occasionally seen flying over the northern ocean or perching on sea ice during the winter. [13] [41]

Steller's Sea eagle occasionally turns up in western Alaska. In December 2021, for the first time, one had been documented in the lower 48 states, first on the Taunton River in Massachusetts and then in Georgetown, Maine. [42] [43]

Vagrancy

A single individual has been moving around North America, having first been seen on August 30, 2020, near Denali National Park in Alaska. [44] Subsequently, a Steller's sea eagle was photographed in Victoria, TX, not long after a winter storm blew into the state. This sighting has been verified by the Texas Bird Records Committee and is presumed to be the same individual as seen in Denali, though the photos are not sufficient to establish this identity. [45] This was the first record of the species in the contiguous United States. The sea eagle was then confirmed in several locations in New Brunswick, Quebec, and Nova Scotia throughout the summer and into November. In December, it was spotted on the Taunton River in Massachusetts and then moved north to the Maine coast (Georgetown, Boothbay, and Pemaquid). [46] More recently, it was seen on the east side on Newfoundland on April 22, 2022. [47] In early 2023, this individual was spotted again in Maine along the shores of Georgetown. [48] Marks on the wing indicate that all these sightings are of the same individual. [49]

Diet

Steller's sea eagles near Rausu, Hokkaido, in Japan: catching a fish (top) and carrying a fish (bottom) Steller's Sea Eagle hunting a fish.jpg
Steller's sea eagles near Rausu, Hokkaido, in Japan: catching a fish (top) and carrying a fish (bottom)

Steller's sea eagle mainly feed on fish. Their favored prey in river habitats are salmon and trout (of the Pacific salmon genus; Oncorhynchus spp.). [50] Among these, pink salmon (O. gorbuscha) and chum salmon (O. keta) are reportedly favored, sometimes intensely supplemented by grayling (Thymallus sp.) and three-spined stickleback (Gastrossteus aculeatus). [51] While pink and chum salmon average approximately 2.2 and 5 kg (4.9 and 11.0 lb) in mature mass, respectively, Steller's sea eagle not infrequently preys on fish up to 6 to 7 kg (13 to 15 lb). [32] In coastal areas, nesting eagles may feed on Bering wolffish (Anarchichas orientalis), Hemitripterus villosus , smooth lumpfish (Aptocyclus ventricosus), and Myoxocephalus spp. [51] Like most Haliaeetus eagles, they hunt fish almost exclusively in shallow water. Relatively large numbers of these normally solitary birds can be seen congregating on particularly productive spawning rivers in August through September due to an abundant food supply. [41]

On Kamchatka, aggregations of as many as 700 eagles have been reported, though much smaller groups are the norm. [13] In summer, live fish, typically in the range of 20 to 30 cm (7.9 to 11.8 in) in length, are fed to the young at the nest. Normally, the parents catch about two or three fish for the young to eat each day. In autumn, when many salmon die after spawning, dead fish tend to be consumed more often than live ones, and these are the main food for Steller's sea eagles that overwinter in inland rivers with unfrozen waters. [30]

On Hokkaido, eagles are attracted by abundant Pacific cod (Gadus macrocephalus), which peak in the Rausu Sea and the Nemuro Straits in February. This resource supports an important commercial fishery, which, in turn, helps to support eagles. [13] Alaska pollock (Gadus chalcogrammus), along with the cod, is the most important food source for wintering eagles in Japan. [4] These eagles may walk boldly within a few feet of fishermen when both are capturing fish during winter, but only familiar ones they have encountered previously. They behave warily and keep their distance if strangers are present. [31]

Alaska pollock, one of the primary food sources for Steller's sea eagles in their wintering range in Japan Alaska Pollock (Gadus chalcogrammus) - GRB.jpg
Alaska pollock, one of the primary food sources for Steller's sea eagles in their wintering range in Japan
Slaty-backed gull, one of the primary avian species hunted by this eagle Slaty backed Gull 20090114.JPG
Slaty-backed gull, one of the primary avian species hunted by this eagle

Fish make up about 80% of the diet of eagles nesting in the Amur River; elsewhere, other prey form almost an equal proportion of the diet. [13] Along the sea coast and in Kamchatka, water birds are the most common prey. Water birds taken by this species include ducks, geese, swans, cranes, herons, and gulls. [52] They also show a strong local preference for slaty-backed gulls (Larus schistisagus). [52]

Common and thick-billed murres (Uria aalge and U. lomvia, respectively) dominated the diet around the Sea of Okhotsk, followed by black-legged kittiwakes (Rissa tridactyla), slaty-backed gulls, crested auklets (Aethia cristatella), and pelagic cormorants (Phalacrocorax pelagicus). [51] Small chicks of murres and cormorants were sometimes taken alive in Russia and brought back to nests, where they independently fed on remains of fish in the eagles' nests until they were killed themselves. [51] In Russia, upland grouse, such as black-billed capercaillie (Tetrao parvirostris) and willow and rock ptarmigan (Lagopus lagopus & L. muta) can be an important prey species; grouse are not typically taken by other Haliaeetus species. [30] [53] Other landbirds hunted by Steller's sea eagles have included short-eared owls (Asio flammeus), snowy owl (Bubo scandiaca), carrion crow (Corvus corone), and common raven (Corvus corax), as well as (rarely) smaller passerines. [51] In one case, a Steller's sea eagle was observed feeding on a great albatross (genus Diomedea), a rare vagrant from the sub-Antarctic oceans. [4] This sea eagle may supplement its diet with various mammals (especially hares [4] [30] ), crabs, mussels, Nereis worms, and squid when given the opportunity. [51] [25]

Mammalian carnivores are apparently readily hunted. Those recorded as prey have included sable (Martes zibellina), American mink (Neogale vison), Arctic fox (Vulpes lagopus), red fox (Vulpes vulpes), and small domestic dogs (Canis familiaris). [30] [51] Smaller mammals have also been recorded as prey, including northern red-backed vole (Clethrionomys rutilus) and tundra vole (Microtus oeconomus). [51] Carrion, especially that of mammals, is readily eaten during the winter. Around 35% of eagles wintering in Japan move inland and feed largely on mammalian carcasses, predominantly sika deer (Cervus nippon). [54] In winter, immature Steller's sea eagles may frequent slaughterhouses to pirate bits of offal. [30] This eagle has been recorded preying occasionally on young seals. It was estimated in one study (Brown & Amadon), that some seal pups carried off in flight by the eagles weighed at least 9.1 kg (20 lb), which (if true) would be the greatest load-carrying ever known for a bird; however, the prey weights were not verified. [55] Often seals and sea lion of any size are eaten as carrion and, using the huge bill, may be dismembered where found rather than flown with. [56]

Steller's sea eagles hunt most commonly from a perch in a tree or rocky ledge located 5–30 m (16–98 ft) above the water, although they may also hunt on the wing, while circling 6–7 m (20–23 ft) above the water. Once located, prey is captured by diving. Eagles sometimes hunt by standing in or near shallow water on a sandbank, spit, or ice-floe, grabbing passing fish. Compared with its white-tailed and bald eagle relatives, Steller's sea eagle reportedly is a more "aggressive, powerful, and active" raptor. [30] Where feeding occurs in groups, kleptoparasitism is common. Kleptoparasitism is most beneficial in procuring food during periods of food abundance and in large feeding aggregations. Immatures use kleptoparasitism as much as adults, but are attacked more often by adults than birds of similar age. Adults appear to benefit most from this behavior. The bold color patterns of adults may be an important signal influencing the formation of feeding groups. However, a video from Russia shows a juvenile Steller's sea eagle aggressively displacing an adult from food during a protracted battle. [57] Outside the breeding period, these eagles probably roost communally near their feeding sites. When salmon and trout are dying in winter after their summer spawning, feeding groups of Steller's sea eagles may mix with smaller golden eagles (Aquila chrysaetos) and white-tailed eagles to exploit this food source. This area is the only one in the golden eagle's nearly circumpolar range where they are extensively dependent on fish for prey. [58]

Kleptoparasitism is sometimes recorded within the species. Occasionally, a smaller species of eagle may steal a fish away from the Steller's, especially if it is distracted by aggression from conspecifics, and both juvenile and adult Steller's may lose fish to the smaller species even face-to-face, especially a less assertive bird, such as immature Steller's. One video shows a golden eagle engaging an immature Steller's in a conflict and ultimately displacing it after maintaining a superior grip despite its smaller size. [59] In other cases, the Steller's have been photographed coming away with the prey after using its superior size to dominate, usually by bearing down its mass and large bill over the smaller eagles. [60] [61] [62] Cinereous vultures (Aegypius monachus) and bearded vultures (Gypaetus barbatus) are the only larger rational birds that a Steller's sea eagle may encounter in the wild.

In other cases, the three eagle species have been observed to feed in close proximity and seem to be outwardly indifferent to each other's presence. In inland areas, where golden, bald, and white-tailed eagles compete over food sources which are not as abundant as these fish and, more importantly, compete for nesting ranges, aggressive interspecies competition can be more common. [13] White-tailed eagles and golden eagles have even killed one another in Scotland, in cases of competition for abutting nesting ranges. [58] As in many sea and fish eagles, Steller's sea eagle may attempt to steal (and occasionally succeed in procuring) fish from osprey (Pandion haliaetus) where they coexist. [63] Steller's sea eagles co-occur with cinereous vultures, the largest living accipitrid, during the winter in the Korean Peninsula and Northeast China. In one case, a cinereous vulture, the largest living accipitrid, was observed to be pursued in flight and kleptoparasitized by a Steller's sea eagle. [64]

Reproduction

An immature in Lodz Zoo, Poland. Steller's sea eagles take several years to reach maturity, attaining the adult color pattern when four Haliaeetus-pelagicus.jpg
An immature in Łódź Zoo, Poland. Steller's sea eagles take several years to reach maturity, attaining the adult color pattern when four

This eagle builds several bulky aeries made of twigs and sticks at a height up to 1.5 m (59 in) and diameter up to 2.5 m (98 in). They usually place such nests high up on trees or on rocky outcrops at 15 to 20 m (49 to 66 ft) above the ground, sometimes in trees up to 45 m (148 ft). Alternate nests are usually built within 900 m (3,000 ft) of each other. In one case, two active nests were found to have been located within 100 m (330 ft). [13] [30]

Courtship usually occurs between February and March, and reportedly simply consists of a soaring flight above the breeding area. [30] It was believed that pairs of sea eagles remain constant throughout life; however, the results of molecular genetic studies show that some chicks have relatively high similarity with chicks from other nests. This can be a clue to occasional polygamy in colonial nesting birds, though alternative hypotheses such as the parents of “conditional” siblings were close relatives exist. [65] Steller's sea eagles copulate on the nest after building it. [4] They lay their first greenish-white eggs around April to May. The eggs range from 78 to 85 mm (3.1 to 3.3 in) height and 57.5 to 64.5 mm (2.26 to 2.54 in) in width and weigh around 160 g (5.6 oz), being slightly larger than those of harpy eagles. [30] Clutches can contain from one to three eggs, with two being the average. Usually, only one chick survives to adulthood, though in some cases as many as three will successfully fledge. [30] After an incubation period around 39 – 45 days the chicks hatch. The chicks are altricial and covered in whitish-down on hatching. The eaglets fledge in August or early September. Adult plumage is attained at four years of age, but first breeding does not typically occur for another year or two. [4] [30]

Eggs and very small nestlings can be preyed on by arboreal mammals, such as sables and ermines, and birds, usually corvids. Any of these small, clever nest predators rely on distraction and stealth to prey on the eagle's nests and are killed if caught by either of the parents. Once they reach roughly adult size in the fledgling stage, few predators can threaten this species. In one case, a brown bear (Ursus arctos) was able to access a nest located on a rock formation and ate a fledgling eaglet, though this is believed to be exceptional. Fully-grown fledglings in tree nests are probably invulnerable to predation. Excluding the Asian black bear (Ursus thibetanus), which has not thus far been recorded as a predator, no other mammalian carnivores equal to or greater than the eagle's size can climb trees in the species' range. [66] Due primarily to egg predation and nest collapses, only 45–67% of eggs are successfully reared to adulthood and up to 25% of nestlings may be lost. [13] Once fully grown, though, the eagle has no natural predators. [41]

Conservation status

Many Steller's sea eagles overwinter in Japan, where they are protected and classified as a national treasure. Steller's Sea Eagles bills up.jpg
Many Steller's sea eagles overwinter in Japan, where they are protected and classified as a national treasure.

Steller's sea eagles are classified as vulnerable by the IUCN. They are legally protected, being classified as a national treasure in Japan and mostly occurring in protected areas in Russia, but many threats to their survival persist. These mainly include habitat alteration, industrial pollution, and overfishing, which in turn decrease their prey source. The current population is estimated at 5,000 and decreasing. [1] Heavy flooding, which may have been an effect of global climate change, caused almost complete nesting failure for the eagles nesting in Russian rivers due to completely hampering the ability of the parents to capture the fish essential to their nestlings' survival. [52] Persecution of the bird in Russia continues, due to its habit of stealing furbearers from trappers. [13] Due to a lack of other accessible prey in some areas, increasingly, eagles on Hokkaido have moved inland and scavenged on sika deer carcasses left by hunters, exposing them to a risk of lead poisoning through ingestion of lead shot. [67]

In Kamchatka, 320 pairs have been recorded. An additional 89 nesting areas are not monitored. In the mountains of Koryakan and along the Bay of Penshina, over 1,200 pairs breed and at least 1,400 juveniles occur. About 500 pairs live in the Khabarovsk region of the Okhostsk coast, and 100 on the Shantar Islands. Another 600 pairs occur in the lower Amur. About 280 pairs are on Sakhalin Island and a few are on the Kurile Islands. The total population is around 3,200 breeding pairs. Possibly, up to 3,500 birds winter on Kamchatka, and another roughly 2,000 may occur on Hokkaido. Generally, the species' outlook is favorable. Outside the breeding range, food bases in the principal wintering areas are so far secure. [13]

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Eagle is the common name for the golden eagle, bald eagle, and other birds of prey in the family Accipitridae. Eagles belong to several groups of genera, some of which are closely related. True eagles comprise the genus Aquila. Most of the 68 species of eagles are from Eurasia and Africa. Outside this area, just 14 species can be found—two in North America, nine in Central and South America, and three in Australia.

<span class="mw-page-title-main">Haast's eagle</span> Extinct species of bird

Haast's eagle is an extinct species of eagle that lived in the South Island of New Zealand, commonly accepted to be the pouākai of Māori legend. It is the largest eagle known to have existed, with an estimated weight of 15 kilograms, compared to the next-largest and extant harpy eagle, at up to 9 kg (20 lb). Its massive size is explained as an evolutionary response to the size of its prey, the flightless moa, the largest of which could weigh 230 kg (510 lb). Haast's eagle became extinct around 1400, following the arrival of the Māori, who hunted moa to extinction, introduced the Pacific rat, and destroyed large tracts of forest by fire.

<span class="mw-page-title-main">Golden eagle</span> Species of eagle

The golden eagle is a bird of prey living in the Northern Hemisphere. It is the most widely distributed species of eagle. Like all eagles, it belongs to the family Accipitridae. They are one of the best-known birds of prey in the Northern Hemisphere. These birds are dark brown, with lighter golden-brown plumage on their napes. Immature eagles of this species typically have white on the tail and often have white markings on the wings. Golden eagles use their agility and speed combined with powerful feet and large, sharp talons to hunt a variety of prey, mainly hares, rabbits, and marmots and other ground squirrels. Golden eagles maintain home ranges or territories that may be as large as 200 km2 (77 sq mi). They build large nests in cliffs and other high places to which they may return for several breeding years. Most breeding activities take place in the spring; they are monogamous and may remain together for several years or possibly for life. Females lay up to four eggs, and then incubate them for six weeks. Typically, one or two young survive to fledge in about three months. These juvenile golden eagles usually attain full independence in the fall, after which they wander widely until establishing a territory for themselves in four to five years.

<span class="mw-page-title-main">Eastern imperial eagle</span> Species of bird

The eastern imperial eagle is a large bird of prey that breeds in southeastern Europe and extensively through West and Central Asia. Most populations are migratory and winter in northeastern Africa, the Middle East and South and East Asia. Like all eagles, the eastern imperial eagle is a member of the family Accipitridae. Furthermore, its feathered legs mark it as a member of the subfamily Aquilinae. It is a large, dark-colored eagle, with a resemblance to other members of the genus Aquila but it is usually the darkest species in its range. This is an opportunistic predator that mostly selects smallish mammals as prey but also a fairly large proportion of birds, reptile and other prey types, including carrion. Compared to other Aquila eagles, it has a strong preference for the interface of tall woods with plains and other open, relatively flat habitats, including the wooded mosaics of the steppe. Normally, nests are located in large, mature trees and the parents raise around one or two fledglings. The global population is small and declining due to persecution, loss of habitat and prey. It has therefore been IUCN Red Listed as Vulnerable since 1994.

<span class="mw-page-title-main">Osprey</span> Species of bird

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.

<span class="mw-page-title-main">Wedge-tailed eagle</span> Bird of prey within the genus Aquila

The wedge-tailed eagle is the largest bird of prey in the continent of Australia. It is also found in southern New Guinea to the north and is distributed as far south as the state of Tasmania. Adults of the species have long, broad wings, fully feathered legs, an unmistakable wedge-shaped tail, an elongated upper mandible, a strong beak and powerful feet. The wedge-tailed eagle is one of 12 species of large, predominantly dark-coloured booted eagles in the genus Aquila found worldwide. Genetic research has clearly indicated that the wedge-tailed eagle is fairly closely related to other, generally large members of the Aquila genus. A large brown-to-black bird of prey, it has a maximum reported wingspan of 2.84 m and a length of up to 1.06 m.

<span class="mw-page-title-main">White-tailed eagle</span> Species of bird

The white-tailed eagle, sometimes known as the 'sea eagle', is a large bird of prey, widely distributed across temperate Eurasia. Like all eagles, it is a member of the family Accipitridae which includes other diurnal raptors such as hawks, kites, and harriers. One of up to eleven members in the genus Haliaeetus, which are commonly called sea eagles, it is also referred to as the white-tailed sea-eagle. Sometimes, it is known as the ern or erne, gray sea eagle and Eurasian sea eagle.

<span class="mw-page-title-main">White-bellied sea eagle</span> Large diurnal bird of prey

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.

<span class="mw-page-title-main">Rough-legged buzzard</span> Species of bird

The rough-legged buzzard (Europe) or rough-legged hawk is a medium-large bird of prey. It is found in Arctic and Subarctic regions of North America, Europe, and Russia during the breeding season and migrates south for the winter. It was traditionally also known as the rough-legged falcon in such works as John James Audubon's The Birds of America.

<span class="mw-page-title-main">Harpy eagle</span> Species of eagle

The harpy eagle is a neotropical species of eagle. It is also called the American harpy eagle to distinguish it from the Papuan eagle, which is sometimes known as the New Guinea harpy eagle or Papuan harpy eagle. It is the largest and most powerful bird of prey found throughout its range, and among the largest extant species of eagles in the world. It usually inhabits tropical lowland rainforests in the upper (emergent) canopy layer. Destruction of its natural habitat has caused it to vanish from many parts of its former range, and it is nearly extirpated from much of Central America. In Brazil, the harpy eagle is also known as royal-hawk. The genus Harpia, together with Harpyopsis and Morphnus, form the subfamily Harpiinae.

<span class="mw-page-title-main">Grey-headed fish eagle</span> Species of bird

The grey-headed fish eagle is a fish-eating bird of prey from South East Asia. It is a large stocky raptor with adults having dark brown upper body, grey head and lighter underbelly and white legs. Juveniles are paler with darker streaking. It is often confused with the lesser fish eagle and the Pallas's fish eagle. The lesser fish eagle is similar in plumage but smaller and the Pallas's fish eagle shares the same habitat and feeding behaviour but is larger with longer wings and darker underparts. Is often called tank eagle in Sri Lanka due to its fondness for irrigation tanks.

<span class="mw-page-title-main">Blakiston's fish owl</span> Species of owl

Blakiston's fish owl, the largest living species of owl, is a fish owl, a sub-group of eagle-owls that specialize in hunting in riparian areas. It is native to China, Japan, and the Russian Far East. This species is a part of the family known as typical owls (Strigidae), which contains most species of owl. Blakiston's fish owl and three other piscivorous owls are placed with some eagle-owls in the genus Ketupa. Its habitat is riparian forest with large, old trees for nest sites that is near lakes, rivers, springs, and shoals that do not freeze in winter. Henry Seebohm named this bird after the English naturalist Thomas Blakiston, who collected the original specimen in Hakodate on Hokkaidō, Japan in 1883.

<span class="mw-page-title-main">Sea eagle</span> Genus of birds

A sea eagle or fish eagle is any of the birds of prey in the subfamily Haliaeetinae of the bird of prey family Accipitridae. Ten extant species exist, currently described with this label.

<span class="mw-page-title-main">Ornate hawk-eagle</span> Species of bird

The ornate hawk-eagle is a fairly large bird of prey from the tropical Americas. Formerly, some authorities referred to this species as the crested hawk-eagle, a name that may cause some confusion as it is more commonly used for an Asian eagle species. Like all eagles, it is in the family Accipitridae. This species has a feathered tarsus that marks it as a member of the Aquilinae or booted eagle subfamily. This species is notable for the vivid colors and bold markings of adults, which differ considerably from the far more whitish plumage of the juvenile bird. The ornate hawk-eagle ranges from central Mexico south through much of Central America and in a somewhat spotty but broad overall range into South America, including in the west apart from the Andes and broadly on the Atlantic side especially Brazil down to as far as Southeast Brazil and northern Argentina. This species is found largely in primary forests with tall trees, although can be found in many forest types.

<span class="mw-page-title-main">African fish eagle</span> Species of bird

The African fish eagle or the African sea eagle is a large species of eagle found throughout sub-Saharan Africa wherever large bodies of open water with an abundant food supply occur. It is the national bird of Malawi, Namibia, Zambia, and Zimbabwe. As a result of its large range, it is known in many languages. Examples of names include: Vis Arend in Afrikaans, nkwazi in Chewa, aigle pêcheur in French, hungwe in Shona, inkwazi in isiZulu, and ntšhu in Northern Sotho. This species may resemble the bald eagle in appearance; though related, the two species occur on different continents, with the bald eagle being resident in North America.

<span class="mw-page-title-main">Pallas's fish eagle</span> Species of bird

Pallas's fish eagle, also known as Pallas's sea eagle or band-tailed fish eagle, is a large, brownish sea eagle. It breeds in the east Palearctic in Kazakhstan, Russia, Tajikistan, Turkmenistan, Uzbekistan, Mongolia, China, India, Nepal, Bangladesh, Myanmar and Bhutan. It is listed as Endangered on the IUCN Red List. It is partially migratory, with Central Asian birds wintering among the southern Asian birds in northern India, and also further west to the Persian Gulf.

<span class="mw-page-title-main">Papuan eagle</span> Species of bird

The Papuan eagle is a large bird of prey. It is also known by several other names, including Papuan harpy eagle, New Guinea eagle, New Guinea harpy eagle, or kapul eagle, the latter name from the local name for a usually arboreal, marsupial that the eagle is known to regularly hunt. This is an endemic species to New Guinea, and it can occasionally be found throughout the island. This is a forest-dwelling species, usually occurring in mature rainforest. The Papuan eagle is a fairly little-known species for a large eagle; however, it is known to prey on a wide range of prey, probably by and large mammals and birds from small to quite large sizes. What little study has been conducted about their breeding habits suggests they nest in a large forest tree, perhaps every other year. The Papuan eagle is probably naturally scarce, but it is under the threat of habitat destruction by deforestation, as well as hunting. Due to its small and declining population, the species has been classified as vulnerable by the IUCN.

<span class="mw-page-title-main">Crested eagle</span> Species of bird

The crested eagle is a large Neotropical eagle. It is the only member of the genus Morphnus. The crested eagle can grow up to 89 cm (35 in) long, with a wingspan up to 176 cm (69 in), and weigh up to 3 kg (6.6 lb). The plumage varies between a light brownish-gray to sooty gray or even blackish in some cases. It has a white throat and a dark spot on the crest and a small dark mask across the eyes. It ranges extensively throughout Central and South America, but not in large numbers. favoring tropical lowland forest. A powerful predator, its diet consist mainly of small mammals, rodents, snakes and smaller birds. Despite their large distribution, they are currently classified as Near Threatened by the IUCN, due mainly to habitat loss

<span class="mw-page-title-main">Dietary biology of the golden eagle</span> Hunting and dietary habits of the golden eagle

The golden eagle is one of the most powerful predators in the avian world. One author described it as "the pre-eminent diurnal predator of medium-sized birds and mammals in open country throughout the Northern Hemisphere". Golden eagles usually hunt during daylight hours, but were recorded hunting from one hour before sunrise to one hour after sunset during the breeding season in southwestern Idaho. The hunting success rate of golden eagles was calculated in Idaho, showing that, out of 115 hunting attempts, 20% were successful in procuring prey. A fully-grown golden eagle requires about 230 to 250 g of food per day. In the life of most eagles, there are cycles of feast and famine, and eagles have been known to go without food for up to a week. Following these periods without food, they will then gorge on up to 900 g (2.0 lb) at one sitting. The powerful talons of the golden eagle ensure that few preys can escape them once contact is made. The talons of this species exert approximately 440 pounds per square inch (3 MPa) of pressure, around 15 times more pressure than is exerted by the human hand, although some claim that the largest individual females may reach a pressure of 750 psi (5.2 MPa). It has been claimed that the golden eagle can lift more than its own body weight in flight. However, other sources claim that a hare, marmot or deer calf weighing 4 kg (8.8 lb) is a struggle for even a large female to carry and that prey much over 2 kg (4.4 lb) would require favorably high wind conditions.

References

  1. 1 2 BirdLife International (2016). "Haliaeetus pelagicus". IUCN Red List of Threatened Species . 2016: e.T22695147A93492859. doi: 10.2305/IUCN.UK.2016-3.RLTS.T22695147A93492859.en . Retrieved 19 November 2021.
  2. "Appendices | CITES". cites.org. Archived from the original on 15 June 2011. Retrieved 14 January 2022.
  3. Sharpe, Richard Bowdler (1874). Catalogue of the Birds in the British Museum. Vol. 1. British Museum. pp. 306–07. Archived from the original on 21 December 2019. Retrieved 2 December 2017.
  4. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Ferguson-Lees, James; Christie, David A. (2001). Raptors of the World. illustrated by Kim Franklin, David Mead, and Philip Burton. London, UK: Christopher Helm. pp. 406–08. ISBN   0-7136-8026-1.
  5. "Fauna on Kamchatka: Brown Bear, Steller's Sea Eagle, Salmon". Archived from the original on 25 February 2019. Retrieved 1 November 2017.
  6. Pallas, Peter Simon (1811). Zoographia Rosso-Asiatica, sistens omnium animalium in extenso Imperio Rossico et adjacentibus maribus observatorum recensionem, domicilia, mores et descriptiones, anatomen atque icones plurimorum. Petropoli. pp. 343–45.
  7. Liddell, Henry George; Scott, Robert (1980) [1871]. A Greek-English Lexicon (Abridged ed.). Oxford, United Kingdom: Oxford University Press. p.  540. ISBN   0-19-910207-4.
  8. Temminck, Coenraad Jacob (1824). Nouveau recueil de planches coloriées d'oiseaux : pour servir de suite et de complément aux planches enluminées de Buffon. Vol. 1. Strasbourg: Chez Legras Imbert et Comp. pp. 87–88. Archived from the original on 9 December 2017. Retrieved 3 December 2017.
  9. Kupfertafeln zur Naturgeschichte der Vögel (in German). Frankfurt: Johann David Sauerländer. 1832. pp. 3–4.
  10. Gray, George Robert (1849). The genera of birds : comprising their generic characters, a notice of the habits of each genus, and an extensive list of species referred to their several genera. Vol. 1. London: Longman, Brown, Green, and Longmans. p. 17. Archived from the original on 9 December 2020. Retrieved 3 December 2017.
  11. Gill, Frank; Donsker, David, eds. (2017). "New World vultures, Secretarybird, kites, hawks & eagles". World Bird List Version 7.1. International Ornithologists' Union. Archived from the original on 26 August 2018. Retrieved 9 December 2017.
  12. "Steller's Sea Eagle – Los Angeles Zoo and Botanical Gardens". Lazoo.org. Archived from the original on 13 June 2011. Retrieved 31 May 2011.
  13. 1 2 3 4 5 6 7 8 9 10 11 12 13 (in Russian) Species Synopsis Steller's Sea Eagle Archived 6 November 2012 at the Wayback Machine . Fadr.msu.ru. Retrieved on 2012-08-21.
  14. 1 2 Wink, Michael; Heidrich, Petra; Fentzloff, Claus (1996). "A mtDNA phylogeny of sea eagles (genus Haliaeetus) based on nucleotide sequences of the cytochrome b gene" (PDF). Biochemical Systematics and Ecology. 24 (7–8): 783–91. doi:10.1016/S0305-1978(97)81217-3. Archived (PDF) from the original on 29 October 2008.
  15. Etymology : niger, Latin for "black".
  16. 1 2 3 Kaiser, M. (2010). "A living specimen of the dark form of Steller's Sea Eagle, Haliaeetus pelagicus ("niger") in captivity". Journal of Ornithology. 152: 207–208. doi:10.1007/s10336-010-0580-2. S2CID   28976663.
  17. 1 2 3 Davies, E. (2010). Dark Steller's sea eagle solves 100 year debate. Archived 9 November 2020 at the Wayback Machine BBC.
  18. 1 2 A rare sea eagle, Skandinavisk Dyrepark, archived from the original on 28 September 2020, retrieved 26 June 2020
  19. 1 2 Dementev, G., & Gladkov, N.A. (1954). Ptitsy Sovetskogo Soyuza [The Birds of Soviet Union]. Sovetskaya Nauka. Moscow, 5, p. 803.
  20. 1 2 3 CRC Handbook of Avian Body Masses, 2nd Edition by John B. Dunning Jr. (Editor). CRC Press (2008), ISBN   978-1-4200-6444-5.
  21. 1 2 3 Saito, K. (2009). Lead poisoning of Steller's Sea Eagle (Haliaeetus pelagicus) and White-tailed Eagle (Haliaeetus albicilla) caused by the ingestion of lead bullets and slugs. Hokkaido Japan. In RT Watson, M. Fuller, M. Pokras, and WG Hunt (Eds.). Ingestion of Lead from Spent Ammunition: Implications for Wildlife and Humans. The Peregrine Fund, Boise, Idaho, USA.
  22. 1 2 Masterov, V. B. (2000). Postnatal development of Steller's sea eagles in East Asia. In First symposium on Steller's and white-tailed sea eagles in East Asia. Wild Bird Society of Japan, Tokyo (pp. 17–28).
  23. Gamauf, A.; Preleuthner, M. & Winkler, H. (1998). "Philippine Birds of Prey: Interrelations among habitat, morphology and behavior" (PDF). The Auk . 115 (3): 713–726. doi:10.2307/4089419. JSTOR   4089419. Archived (PDF) from the original on 23 August 2014. Retrieved 19 September 2014.
  24. Steller's Sea Eagle Archived 6 September 2012 at archive.today . polarconservation.org. last update: 21 April 2009
  25. 1 2 "Steller's Sea Eagles". Animals.nationalgeographic.com. Archived from the original on 7 July 2007. Retrieved 31 May 2011.
  26. Steller's Sea Eagle – The Cincinnati Zoo & Botanical Garden Archived 2 December 2016 at the Wayback Machine . Cincinnatizoo.org (20 June 2014). Retrieved on 2016-12-14.
  27. Japan's Winter Wildlife Zoom In @ National Geographic Magazine. Ngm.nationalgeographic.com. Retrieved on 2017-1-29.
  28. Palmer, R. S. (Ed.). (1988). Handbook of North American Birds Volume VI: Diurnal Raptors (Part 1). Yale University Press.
  29. Fischer, W. (1959). Die Seeadler (1st edition). Neue Brehmn-Bucherei no. 221 (3d rev. ed. 1982).
  30. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Brown, Leslie and Amadon, Dean (1986) Eagles, Hawks and Falcons of the World. The Wellfleet Press. ISBN   978-1555214722.
  31. 1 2 Tingay, R. E., & Katzner, T. E. (Eds.). (2010). The eagle watchers: Observing and conserving raptors around the world. Cornell University Press.
  32. 1 2 3 Ladyguin, Alexander (2000). The morphology of the bill apparatus in the Steller's Sea Eagle Archived 7 February 2012 at the Wayback Machine . First Symposium on Steller's and White-tailed Sea Eagles in East Asia pp. 1–10; Ueta, M. & McGrady, M.J. (eds.) Wild Bird Society of Japan
  33. Nakagawa, H. (2009). "Steller's Sea Eagle" (PDF). Bird Research News. 6 (2): 2–3. Archived (PDF) from the original on 12 April 2016. Retrieved 14 December 2016.
  34. Tabaranza, Blas R. Jr. (17 January 2005). "The largest eagle in the world". Haribon Foundation. Archived from the original on 13 December 2012. Retrieved 23 September 2012.
  35. A field guide to the Birds of Korea (2005). ISBN   89-951415-3-0.
  36. "Steller's Sea-Eagle". San Diego Zoo. Archived from the original on 14 November 2020. Retrieved 23 October 2012.
  37. Whitfield, D. Philip; Duffy, Kevin; McLeod, David R. A.; Evans, Richard J.; MacLennan, Alison M.; Reid, Robin; Sexton, David; Wilson, Jeremy D.; Douse, Andrew (2009). "Juvenile Dispersal of White-Tailed Eagles in Western Scotland". Journal of Raptor Research. 43 (2): 110. doi:10.3356/JRR-08-54.1. S2CID   85815476.
  38. McGrady, Michael J.; Ueta, Mutsuyuki; Potapov, Eugene R.; Utekhina, Irina; Masterov, Vladimir; Ladyguine, Alexander; Zykov, Vladimir; Cibor, Jack; Fuller, Mark; Seegar, William S. (2003). "Movements by juvenile and immature Steller's Sea Eagles Haliaeetus pelagicus tracked by satellite". Ibis. 145 (2): 318. doi:10.1046/j.1474-919X.2003.00153.x.
  39. "BRUCE MACTAVISH: What will become of the solitary Steller's sea eagle, the displaced flying beast from Siberia now roving the Newfoundland coastline? | SaltWire". Archived from the original on 7 December 2023. Retrieved 6 December 2023.
  40. Shivaram, Deepa "A lost eagle from Asia has been traveling around North America for more than a year" NPR (Dec. 21, 2021) Archived 22 December 2021 at the Wayback Machine Accessed Dec. 21, 2021
  41. 1 2 3 4 "ADW: Haliaeetus pelagicus: Information". Animaldiversity.ummz.umich.edu. Archived from the original on 24 May 2011. Retrieved 31 May 2011.
  42. Fleming, Deidre (31 December 2021). "Birders cap off 2021 with a first-ever sighting of a Steller's sea eagle in Maine". Portland Press Herald. Archived from the original on 4 October 2022. Retrieved 5 December 2022.
  43. "Rare Steller's sea eagle travels far from home to Maine coast". The Washington Post. Associated Press. 29 January 2022. Archived from the original on 5 February 2023. Retrieved 5 December 2022.
  44. The Story of America's Rarest Eagle, archived from the original on 8 January 2022, retrieved 8 January 2022
  45. Texas Bird Records Committee Report for 2021, archived from the original on 8 February 2023, retrieved 7 February 2023
  46. "RARE BIRD ALERT: STELLER'S SEA-EAGLE". Maine Audubon. 31 December 2021. Archived from the original on 8 January 2022. Retrieved 8 January 2022.
  47. "STELLER'S SEA-EAGLE". Merlin eBird. 22 April 2022. Archived from the original on 6 January 2024. Retrieved 25 April 2022.
  48. "Twitter". Twitter. Retrieved 7 February 2023.
  49. "Inside the Amazing Cross-Continent Saga of the Steller's Sea-Eagle". Audubon. 10 January 2022. Archived from the original on 25 January 2022. Retrieved 25 January 2022.
  50. "Steller's sea eagle videos, photos and facts – Haliaeetus pelagicus". ARKive. 17 April 2003. Archived from the original on 8 December 2009. Retrieved 31 May 2011.
  51. 1 2 3 4 5 6 7 8 Utekhina, I., Potapov, E., & McGRADY, M. J. (2000). Diet of the Steller's Sea Eagle in the northern Sea of Okhotsk Archived 24 August 2013 at the Wayback Machine , pp. 71–92 in First Symposium on Steller's and White-tailed Sea Eagles in East Asia. Tokyo, Japan: Wild Bird Society of Japan.
  52. 1 2 3 Potapov, E., U. Irina, M. McGrady, and D. Rimlinger. (2010). (Abstract) Source-sink populations of the Steller's Sea Eagles (Haliaeetus pelagicus) in the northern part of the Sea of Okhotsk: ecological traps and their conservation implications. P.32 in S. Gombobaatar, R. Watson, M. Curti, R. Yosef, E. Potapov, and M. Gilbert (eds.) Asian raptors: science and conservation for present and future: The proceedings of the 6th International Conference on Asian Raptors. Asian Raptor Research and Conservation Network, Mongolian Ornithological Society, and National University of Mongolia, Ulaanbaatar, Mongolia.
  53. "Steller's sea eagle Haliaeetus pelagicus". The Peregrine Fund: Global Raptor Information Network. 12 February 2012. Archived from the original on 9 December 2020. Retrieved 9 March 2013.
  54. Ueta, Mutsuyuki; McGrady, Michael J.; Nakagawa, Hajime; Sato, Fumio; Masterov, Vladimir B. (2003). "Seasonal change in habitat use in Steller's sea eagles". Oryx. 37. doi: 10.1017/S003060530300019X .
  55. Wood, The Guinness Book of Animal Facts and Feats. Sterling Pub Co Inc. (1983), ISBN   978-0-85112-235-9.
  56. BirdLife International (2003). BirdLife's online World Bird Database: the site for bird conservation. Version 2.0. Cambridge, UK: BirdLife International.
  57. "Wild Russia- Eagles Battle Over Food". YouTube. Retrieved 4 June 2013.[ dead YouTube link ]
  58. 1 2 Jeff Watson (23 August 2010). The Golden Eagle. A&C Black. ISBN   978-1-4081-1420-9 . Retrieved 23 October 2012.
  59. "Kamatchka:Golden Eagle fights Steller's Sea Eagle". Archived from the original on 8 October 2014. Retrieved 19 September 2014.
  60. Steller's sea eagle photo – Haliaeetus pelagicus – G113853 Archived 5 May 2013 at the Wayback Machine . ARKive. Retrieved on 2012-08-21.
  61. The Secret Lives of Sea Eagles – National Wildlife Federation Archived 18 February 2011 at the Wayback Machine . Nwf.org (26 October 2011). Retrieved on 2012-08-21.
  62. Photo Keywords : steller's sea eagle : White-tailed Eagle and Steller's Sea Eagle Archived 4 March 2016 at the Wayback Machine . Golden First Light (21 June 2012). Retrieved on 2012-08-21.
  63. "Steller's Sea-Eagle". Woodland Park Zoo Seattle WA. Archived from the original on 25 September 2014. Retrieved 22 September 2014.
  64. "Birds Korea- Bird News January 2006". Birds Korea. Archived from the original on 22 February 2014. Retrieved 22 May 2013.
  65. Мастеров, В. Б., and М. С. Романов. "Тихоокеанский орлан Haliaeetus pelagicus: экология, эволюция, охрана." (2014): 384-384.
  66. McGrady, M. J.; Potapov, E.; Utekhina, I. (1999). "Brown bear (Ursus arctos) feeds on Steller's Sea Eagle (Haliaeetus pelagicus) nestling". Journal of Raptor Research. 33 (4): 342–343. Archived from the original on 9 December 2020. Retrieved 14 December 2016.
  67. BirdLife International (2016) Species factsheet: Haliaeetus pelagicus Archived 21 October 2016 at the Wayback Machine .

Further reading