Justification of Red List category
This species has a small, regionally declining population as a result of displacement following habitat conversion in its breeding grounds, mortality caused by lead poisoning in inland Japan, reduced breeding rate in the Magadan District caused by climate change, and reduced breeding success predominantly due to predation of nestlings by brown bears on Sakhalin Island. It is suspected that it will decline at a rate of 20-30% over three generations in the future as significant threats are ongoing, and some (such as climate change) are predicted to worsen. It therefore qualifies as Vulnerable.
M. McGrady et al. (in litt. 2012) estimated the global population to number c.4,600-5,100 individuals, including c.1,830-1,900 breeding pairs, assumed to be equivalent to c.3,600-3,800 mature individuals. However, Masterov and Romanov (2014) estimate the global population to be 6,000-7,000, which roughly equates to 4,000-4,670 mature individuals. It is placed in the band 4,600-7,000 individuals, and 3,600-4,670 mature individuals.
The species is suspected to be in moderate decline, owing to displacement following habitat conversion in its breeding grounds, mortality caused by lead poisoning in inland Japan, reduced breeding rate in the Magadan District caused by climate change, and reduced breeding success predominantly due to predation of nestlings by brown bears on Sakhalin Island.
Surveys of territorial pairs along the coastline and rivers of the northern part of the Sea of Okhotsk during 1991-1998 found a significant decline (from 70% to 35%) in the percentage of pairs taking part in breeding and in the number of chicks fledged per territorial pair (Potapov et al. 2000). More recent surveys in the same area have also found a decline in the number of chicks fledged per successful pair over the last 10 years (Potapov et al. 2018). The declining breeding rate of eagles nesting along rivers is associated with increasing frequency and intensity of spring floods, which impede successful hunting and therefore reduce breeding output (Potapov et al. 2018). Reduced breeding rate in coastal pairs is associated with reduced ice cover in spring (Potapov et al. 2018).
Simulation modelling of the population of H. pelagicus wintering in Hokkaido, northern Japan, predicted a population decline from 1,500 individuals to a mean of 934.6 individuals over 100 years (Ueta & Masterov 2000), equating to a decline of 20% over three generations, caused predominantly by adult mortality due to lead poisoning.
Surveys on Sakhalin Island have revealed a decrease in breeding productivity in recent decades from 0.8-1.4 fledglings per occupied territory per year in the 1980s and 1990s (Masterov et al. 2000; Masterov 1995, cited in Romanov & Masterov 2020) to 0.54 fledglings per occupied territory per year in recent years (Masterov et al. 2018, cited in Romanov & Masterov 2020), with a similar trend in the Amur region, Russia (Romanov & Masterov 2020). The species remains abundant in both areas, however the proportion of immature to adult individuals has decreased (Masterov et al. 2018, cited in Romanov & Masterov 2020). Romanov & Masterov (2020) carried out modelling showing that if current fecundity does not change, the populations on Sakharov and in the Amur region will decline by 0.6% and 0.95% per year respectively, equating to a declines of 24% and 36% over three generations (although actual rates may be lower than this due to recruitment of "floater" individuals into the breeding population as the population declines).
The decline of this species is complex - a long generation time combined with declining reproductive output may cause a time-lag in overall population decline (Romanov & Masterov 2020). As there is evidence of a decline in breeding productivity in several parts of the range, and significant threats to both adult survival and breeding productivity are ongoing, with some predicted to worsen in the future (e.g. extreme weather conditions brought about by climate change), it is precautionarily suspected to have declined at a rate of 15-25% in the past, and to decline at a rate of 20-30% in the future.
Haliaeetus pelagicus breeds on the Kamchatka peninsula, the coastal area around the Sea of Okhotsk, the lower reaches of the Amur river (south to the Gorin river) and on northern Sakhalin and Shantar, Russia. A few hundred winter in Kamchatka, the northern Sea of Japan, and the coast of Okhotsk, but most (c.2,000) winter in the southern Kuril islands and Hokkaido, Japan. It is an uncommon winter visitor to north-eastern China, North Korea and South Korea. Declining breeding success has been noted in the inland river populations of Magadan district, Russia, from 1991 to 2009, with a slow increase in the breeding success of coastal populations over the same period, suggesting that they can be considered sink and source populations respectively (Potapov et al. 2010, 2012). Its total population is estimated at 3,600-4,670 mature individuals and declining overall.
It breeds on sea coasts and inland near larger rivers (mostly on lower stretches) or lakes, where there are stands of mature trees. In the Magadan district of Russia, successful breeding pairs along coasts appear to produce more fledged chicks than successful pairs on rivers, and average brood size is larger for coastal pairs (Potapov et al. 2010, 2012). Annual net chick production showed an increase in constantly monitored coastal sites, but a decrease in river sites (Potapov et al. 2012). During the autumn birds forage along rivers where dead salmon are abundant. During mid-winter, birds in Russia tend to remain on the coast, except some that winter in Kamchatka along inland rivers fed by hot springs and at Lake Kurilskoye (M. McGrady et al. in litt. 2012), while those wintering in Japan mainly stay near freshwater, but c.35% move to mountainous areas where many feed on deer carcasses (Ueta et al. 2003).
In Russia, it is threatened by habitat alteration during the development of hydroelectric power projects, proposed large-scale coastal and offshore developments for the petrochemical industry, and logging for timber (Ferguson-Lees and Christie 2001). Industrial pollution of rivers and high levels of DDT/DDE, PCBs and heavy metals are further threats (Iwata et al. 2000; Kim et al. 1999). Over-fishing has caused a decline of fish stocks in Russia and Japan which has led to an increasing tendency of birds on Hokkaido to move inland and scavenge on sika deer carcasses left by hunters, exposing them to a risk of lead poisoning through ingestion of lead shot (Ferguson-Lees & Christie 2001). Despite laws being introduced in Japan in 2004 prohibiting the use of lead ammunition for hunting large animals, and further laws in 2014 prohibiting possession of lead ammunition, lead poisoning continues to be a significant threat (Ishii et al. 2017). On Sakhalin Island, the most significant threat to breeding success is nestling predation by brown bears, while other threats include adverse weather (which may form ecological traps on migration routes), food shortages due to overfishing, habitat alteration, disturbance at nest sites, and infection by the blood parasite haemosporida (Romanov and Masterov 2020). Shooting may also be a local threat in parts of the wintering range (GRIN 2021). Declines in reproductive output along the coastline and rivers of the northern part of the Sea of Okhotsk are predominantly caused by increasing frequency and intensity of spring floods, which impede successful hunting and therefore reduce breeding output, and reduced ice cover in spring (Potapov et al. 2018).
Conservation Actions Underway
CITES Appendix II, CMS Appendix I and II, Raptors MOU Category 1. It is legally protected in Russia, Japan, China and South Korea. It is monitored in several protected areas in Russia, including the Magadan State Nature Reserve, Kronotski State Reserve, Lake Krontskoea Wildlife Refuge and Kava Wildlife Refuge (Magadan), the Orel' and Udyl' Wildlife Refuges and Dzhugdzhurskiy, Shantarsky and Komsomol'ski Nature Reserves (Khabarovsk), the Poronayskiy Nature Reserve (Sakhalin), and the Kuril'ski Nature Reserve (Kuril Islands). In Japan, the key wintering grounds on Hokkaido, Shiretoko and Furen-ko are designated as National Wildlife Protection Areas.
85-94 cm. Huge, unmistakable eagle with massive yellow bill in adults. Adults have blackish-brown plumage with white shoulders and white, wedge-shaped tail. Dark morph lacks white shoulders.
Text account compilers
North, A., Bird, J., Taylor, J. & Benstead, P.
BirdLife International (2024) Species factsheet: Haliaeetus pelagicus. Downloaded from https://datazone.birdlife.org/species/factsheet/stellers-sea-eagle-haliaeetus-pelagicus on 24/02/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from https://datazone.birdlife.org on 24/02/2024.