Steller’s Sea-Eagle
( Haliaeetus pelagicus )
The First Record of Steller’s Sea-Eagle (Haliaeetus pelagicus) in British Columbia and Canada. By Rick Toochin, Peter Hamel, and Margo Hearne. Published: June 3, 2023.
Introduction and Distribution
The Steller’s Sea-Eagle (Haliaeetus pelagicus) is one of the rarest and most spectacular raptors in the world (Brazil 1993). This incredible species is found breeding in North-eastern Asia along rocky coasts, near coastal lagoons and river mouths, nesting in large trees or rock crags from the coastal regions along the Western Bering Sea, south of Paul’s Bay (Koryakland), and around Sea of Okhotsk (Brazil 2009, Meyburg et al. 2020). The overall population is small and is regionally declining (BirdLife International 2020). This species is listed as vulnerable by BirdLife International, and the global population is currently estimated to number about 4600–5100 individuals, including about 1830–1900 breeding pairs, which is believed to number about 3600–3800 mature individuals (BirdLife International 2020). This overall total has apparently declined from about 7500 birds in the 1990s (Meyburg et al. 2020). Most birds (1200–1500 pairs) breed on the Kamchatka Peninsula, with 1100 birds in Amurland and 560 on Sakhalin Island (Brazil 2009, Meyburg et al. 2020). There are about 2000 birds that winter on the island of Hokkaido in Japan (Meyburg et al. 2020). Declining breeding success of inland river populations of Magadan from 1991 to 2009, and slow increase in success of coastal populations over same period, suggests that former can be considered a sink population and the latter a source population (Potapov et al. 2010, 2012). This species formerly bred in Korea, but is now only an uncommon winter visitor there, and few recent winter records in northeastern China (records in March 1988 and 1989 believed to be the first since the 1940s) (Meyburg et al. 2020). The main problems putting this species at risk include habitat alteration, with large-scale destruction of old forests, but also development of hydro-electric power projects, and proposed large-scale coastal and offshore developments for petrochemical industry; lead-poisoning from ingestion of lead shot; industrial pollution of rivers; shooting by hunters; and natural collapse of eyries (Meyburg et al. 2020). Conservation measures recommended include payment of compensation to hunters for skins damaged by eagles; populations must be thoroughly monitored in the future (Meyburg et al. 2020). This raptor is legally protected in Russia, Japan, China and South Korea (Meyburg et al. 2020). It is monitored in several protected areas in Russia, including Magadan State Nature Reserve, Kronotski State Reserve, Lake Krontskoea and Kava Wildlife Refuges (Magadan), Orel' and Udyl' Wildlife Refuges and Dzhugdzhurskiy, Shantarsky and Komsomol'ski Nature Reserves (Khabarovsk), Poronayskiy Nature Reserve (Sakhalin), and Kuril'ski Nature Reserve (Kuril Islands) (Meyburg et al. 2020). In Japan, the key wintering grounds on Hokkaido Island, such as Shiretoko and Furen-ko, have been designated National Wildlife Protection Areas (Meyburg et al. 2020).
The Steller’s Sea-Eagle is a short distance migrant (Brazil 2009). Birds move south from the breeding areas in October, returning in March and April (Meyburg et al. 2020). Adults take 21–25 days to make return migration, but young take 31–61 days; in the autumn birds arrive in Japan in November, immatures remaining there until May, exceptionally even till mid-June (Meyburg et al. 2020). The chief overwintering areas outside the breeding range are in the Southern Primorski region, Kuril Islands and Sakhalin Island; since 1980, many birds (exceptionally up to 2000 and 90% of the Japanese wintering population) have overwintered on Hokkaido, particularly on the east coast at Shiretoko Peninsula (Meyburg et al. 2020) .
Elsewhere in Japan, this species is rare from Honshu south to Kyushu and Okinawa (Brazil 2009). However, it is estimated that a major part of the Kamchatkan sub-population does not leave the peninsula, but merely moves to the southern parts of it (Brazil 2009, Meyburg et al. 2020). A young bird tracked by satellite remained in the nest area in Kamchatka for nearly 2 months after fledging, up to mid-October; within 3 weeks it migrated 1360 km south through the Kuril Islands to Urup (Meyburg and Lobkov 1994), northeast of Hokkaido, (McGrady et al. 2003, Meyburg et al. 2020). The young birds move north in the spring later and over shorter distances than the adult birds (McGrady et al. 2003, Meyburg et al. 2020). Adults arrive on the summer breeding grounds when sea-ice is still extensive (Meyburg et al. 2020). In a satellite-tracking study in 1997–1999, 24 juveniles hatched in Magadan, Kabarovsk, Amur, Sakhalin and Kamchatka were tracked: initial dispersal took place between September 9 and December 6, but occurs mainly from September 14–October 21, with no regional differences; birds move in migration mostly along previously known routes from September 9–January 18, and for 18 individuals completed in 4–116 days, most making stopovers of 4–28 days; individuals concentrated in 1–3 subareas within winter ranges, mean size of first subareas 274 km², of second 529 km², of third 1181 km² (Meyburg et al. 2020). The start of spring migration occurs between February 2 and March 31; two young from Magadan tracked to summering grounds (both had early-summer and late-summer areas) well south of natal areas, one of them (tracked for 25 months) initiated second autumn migration in the first half October, and arrived on the wintering grounds on December 26 having covered 1839 km (in contrast to a first winter bird, this eagle exploited only one subarea in 1998–1999, but the near areas used in previous winter), left wintering ground between April 13 and May 13, and arrived back in its summering area between June 7 and July 8 (Meyburg et al. 2020).
The world’s entire population of Steller’s Sea Eagles spend the winter from Ussuriland, south into Korea and Japan at Hokkaido and northern Honshu (Brazil 2009, Meyburg et al. 2020). Winter habitat includes inland to large lakes and wetlands, also coastal lagoons where it may congregate near rich food supplies of fish and waterfowl (Brazil 2009).
Vagrants have been recorded up to 3000 km from their regular range on Kure Island and Midway Island in the Hawaiian Islands and wandering birds have been recorded as far afield as Anadyr, Yakutsk in Siberia, and in Beijing China (Brazil 2009, Meyburg et al. 2020). In North America, the Steller’s Sea-Eagle is a casual vagrant migrant species only in western Alaska and various parts of southwestern Alaska with at least seven records, some of them involving long-staying individuals, mostly on Pribilofs Islands and Aleutian Islands (Howell et al. 2014, Gibson and Withrow 2015). In British Columbia, this species is a recent addition to the Provincial Bird List with a photographed immature from Masset, on Haida Gwaii (P. Hamel Pers. Comm.).
An adult bird photographed at Mile post 43 of the Denali Highway, just west of MacLaren River, in Matanuska-Susitna County in Alaska on August 30, 2020, has been tracked through photographs from Goliad County, Texas, in March 2021, and New Brunswick, north to Quebec, and southeast to Nova Scotia in the summer and fall of 2021, and to Massachusetts in December 2021 and to Maine in 2022 (e-bird database 2021). This is the only record for Eastern North America.
Identification and Similar Species
Though the Steller’s Sea-Eagle is a very rare vagrant in North America, most field guides do illustrate this species. The size varies from males and females with birds measuring 85–105 cm in length (Brazil 2009); the male weighs between 4900–6000 g, and the female weighs between 6800–9000 g (Brazil 2009, Meyburg et al. 2020). The wingspan is huge measuring 195–245 cm (Brazil 2009, Meyburg et al. 2020). This species takes over 5 years to mature (Howell et al. 2014). Adults are unmistakable owing to their immense size, paddle-shaped wings, blackish-brown plumage with large white shoulders, and leading edge of the wings, and large white wedge-shaped tail (Meyburg et al. 2020). There is a white patch on the forehead that sometimes extends to crown (Brazil 2009). The bill depth is particularly impressive as it is very deep, strongly arched, and thick, hooked, and is deep yellow including the gape and lores (Brazil 2009, Meyburg et al. 2020). Female has identical plumage but is up to 19% larger in size and can be 79% heavier with a deeper bill (Meyburg et al. 2020). The iris, the cere and eye ring are yellow (Brazil 2009). The massive legs are orange-yellow and are paler yellow in young birds, have white feathered leggings, and have large yellow feet (Masterov et al. 2018, Meyburg et al. 2020). Juveniles are variable in plumage, initially are blackish overall with pale axillaries and grey streaks overhead and breast, white mottling on median wing-coverts/inner secondaries, and dark-tipped dirty-white tail, and enormous pale horn-coloured bill (Masterov et al. 2018, Meyburg et al. 2020). Immature has more sharply wedge-shaped tail and heavier bill than young White-tailed Eagle (Haliaeetus albicilla) (Brazil 2009, Meyburg et al. 2020). As birds age, the tail, thighs, and forewing whiten steadily, becoming progressively cleaner and tail whiter, whiter forehead blaze last to develop (Masterov et al. 2018, Meyburg et al. 2020). The amount of white on the base of the tail various from very dark with spots and the tail base and gets progressively whiter as birds age into maturity (Masterov et al. 2018). Birds reach adult plumage and sexual maturity when they are about 4 years old (Meyburg et al. 2020). Steller’s Sea-Eagles fly with their wings in a strong dihedral (Wheeler and Clark 1995, Clark and Wheeler 2001).
A speculated subspecies, possibly a dark morph or an aberrant possibly mis-identified sub-adult, (Haliaeetus pelagicus niger) differed in being all black in plumage except for having an all-white tail (Brazil 2009, Meyburg et al. 2020). These birds were found in Korea and in the Russian Far East but, today there are only specimen records, and it is now believed to be most likely extinct (Brazil 2009).
The Bald Eagle (Haliaeetus leucocephalus) is a smaller sized raptor species measuring 79-94 cm in length, with a wingspan of 178-229 cm, and weighing 4,325 grams (Sibley 2000, Dunn and Alderfer 2011). Bald Eagles take 4-5 years to reach full maturity (Wheeler 2003). Overall, Bald Eagles have a smaller bill, shorter neck, lacks a large wedge-shaped tail at any age, and flights with its wings flat to the horizontal plan any strong dihedral pattern in flight (Wheeler 2003).
Occurrence and Documentation
The Steller’s Sea-Eagle is a new addition to the avifauna list of British Columbia. This new record for the province involves an immature bird found by Althea Lean, Peter Hamel, and photographed by Margo Hearne at North Beach, outside of Masset, Haida Gwaii on June 9, 2019 (P. Hamel Pers. Comm.). This bird was found sitting loosely amongst a couple of Bald Eagles and was huge by comparison in overall size and bill shape (P. Hamel Pers. Comm.). After getting photographed by Margo Hearne the bird took flight and despite a large-scale effort was not relocated (P. Hamel Pers. Comm.). This timing of this bird fits an overall pattern of vagrancy by birds from Asia that move across the Aleutian Islands in the month of May, into early June (Gibson and Withrow 2015) and end up arriving on Haida Gwaii in the month of June (P. Hamel Pers. Comm.). A couple of species examples include Lesser Sand-Plover (Toochin and Haviland 2015b) and Common Cuckoo (Toochin et al. 2019a). There are also examples of Asian vagrants such as the Common Cuckoo having been found along the Alaskan Panhandle in Sitka, Alaska from June 9-15, 2015 (Heinl 2015). There is also the recent record of the Gray-tailed Tattler that was found in Kitimat from June 26-29, 2020 (Swick 2020). As more coverage is given to this region in the future it is likely more spring overshoots will be found from Asia.
Of note was a 3rd year eagle observed from December 8-21, 2004, at Goldstream Regional Park, outside Victoria, was never definitively identified to species (Clark 2008). This bird was thought by some to be the offspring of a Bald Eagle and Steller’s Sea-Eagle pairing (Clark 2008).
Acknowledgements
We want to thank Wings Tour leaders Gavin Bieber and Susan Myers for their help in establishing the identification on the Steller’s Sea-Eagle. All photos are used with permission of the photographer and are fully protected by copyright law. Photographs are not to be reproduced, published or retransmitted on any website without the authorization of the photographer.
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