VU
Steller's Eider Polysticta stelleri



Justification

Justification of Red List Category
This species is listed as Vulnerable because it is undergoing a rapid population reduction, particularly in the key Alaskan populations. Further studies are needed to determine the causes of these declines, and whether some populations may have shifted to unsurveyed areas within the range.

Population justification
Various population estimates include: c.10,000-15,000 wintering individuals in north Norway and the south-east Baltic (based on a count of 4,297 off Kola Peninsula in April 2003 [Krasnov et al. 2004], 2,300 in the whole Baltic in 2009 (Skov et al., 2011) and c.2,700 wintering off Norway in the same year (Aarvak et al. 2012) Ce.100,000-110,000 wintering individuals were counted in the north Pacific; counts in North America declined from 137,900 in 1992 to 77,300 in 2003, forming the basis of the 2003 North American population estimate of 90,000-95,000 individuals (K. Laing in litt. 2005 to Wetlands International 2006). However, the population has since declined to 74,400 individuals in 2011 (Larned 2012). Ce.20,000 individuals migrate through the Kamchatka Peninsula in spring (Gerasimov and Gerasimov 2003), c.100-10,000 breeding pairs and c.23,000 wintering individuals were recorded in Russia in March 2009 (Aarvak et al. 2012). The minimum European population in winter is currently estimated at 30,800-41,200 individuals, which equates to 20,500-27,500 mature individuals (BirdLife International 2015). There is also a marginal breeding population in Europe estimated at 5-50 pairs, which equates to 10-100 mature individuals (BirdLife International 2015). Based on the current European wintering population estimate of 30,800-41,200 individuals (BirdLife International 2015) and an estimate of 100,000-110,000 individuals wintering in the north Pacific, the total population is estimated at c.130,000-150,000 individuals.

Trend justification
Based on population estimates of birds staging in southwest Alaska, the Alaskan population declined by 2.3% per year since 1992 (or 46% over 20 years) during 1992-2011 (Larned 2012). Declines in Europe have been even steeper, with an estimated decline of 66.4% between Baltic-wide surveys in 1993 and 2009 (Skov et al. 2011). It is unclear, however, whether these declines were genuine, or reflect a redistribution to other wintering areas, including Russia (Aarvak et al. 2012). Conservatively assuming the Asian population was stable over this time, and taking into account the smaller relative size of the European population, a precautionary decline rate of 30-49 % over 12 years is assumed.  

Distribution and population

This species breeds between the Kolyma Delta and the Yamal Peninsula, Russia, and on the Arctic plain of Alaska, U.S.A. (C. Dau in litt. 1999, Frederickson 2001). A remnant population breeds in western Alaska. Non-breeding populations summer in Novaya Zemlya, Russia, northern Norway and adjacent Russian waters, and south-west Alaska (C. Dau in litt. 1999). Birds breeding east of the Khatanga Gulf, Russia, winter in the Bering Sea. Small numbers winter in northern Japan. Birds breeding west of the Khatanga Gulf winter in the north-east Atlantic Ocean and the Baltic Sea. 

Ecology

Behaviour This species is migratory (del Hoyo et al. 1992). It begins to breed in June, nesting sometimes in single pairs in very low densities (roughly one pair per 100 acres was recorded on the Kashunuk River in the 1960s) (Johnsgard 1978), but occasionally in small colonies of up to 60+ nests (Kear 2005). Around the time of hatching, males gather in large flocks off the coast near the breeding ground (Johnsgard 1978). Shortly after hatching, the female moves her brood to the coast where they form 'herds' (Johnsgard 1978). The species migrates up to 3000km to its moulting sites (Johnsgard 1978, Kear 2005), where it becomes flightless for a period, before some continue migration to more distant wintering sites (Petersen et al. 2006). The timing of the moult migration appears to be highly variable, occurring sometimes as early as August, but in some years not until November, in which case the moult occurs prior to arrival (Johnsgard 1978). On the moulting grounds it forms flocks that may exceed 50,000 birds (Laubhan and Metzner 1999, Kear 2005). Congregations of a similar size also occur also in the spring when pair formation occurs prior to departure for the breeding grounds (Kear 2005). Spring migration commences in March in East Asia (Kear 2005). Elsewhere it begins in April, usually peaking in May (Kear 2005). Arrivals on the breeding grounds begin in early June (Kear 2005). Some small flocks remain throughout the summer in the wintering quarters at Varangerfjiord (Kear 2005). Habitat Breeding This species regularly breeds several kilometres inland (Kear 2005). It inhabits pools of various shapes and sizes in areas that characterise flat coastal belt within open tundra (Kear 2005). In the Lena Delta and Barrow areas it favours moss-lichen polygonal tundra (Kear 2005). It forages in areas of fresh, saline or brackish water, as well as in tidal flats (Johnsgard 1978). Following hatching all birds move to coastal habitats (Johnsgard 1978). Non-breeding It winters mostly at sea, along low-lying rocky coasts, frequenting bays and river mouths (del Hoyo et al. 1992). It forages in water that is less than 10m deep (Madge and Burn 1988), and particularly favours areas where freshwater streams enter the sea (Madge and Burn 1988). Diet It feeds chiefly on molluscs, crustaceans and other marine invertebrates (del Hoyo et al. 1992). During the breeding season, some freshwater prey is taken including chironomid and caddisfly larvae (Johnsgard 1978). During moult, bivalve molluscs are the primary food source (Petersen 1981). Breeding site Nests are built on small hummocks or in depressions between hummocks, usually within a few metres of a tundra pond, and are often well-concealed by grass (Johnsgard 1978). The nests are deep and lined with lichens, grass and down (Kear 2005).

Threats

Through a variety of effects, climate change potentially represents the greatest threat to the species. Recent dramatic changes in Arctic sea ice extent and thickness north of Alaska and Russia may affect eiders in unknown ways. In addition, climate change is causing the loss of Arctic tundra ponds (Andresen and Lougheed 2015), which could be contributing to declines in the species. In general, climate change is predicted to cause dramatic habitat changes in the Arctic region (Fox et al. 2015). Increased predation may also result from climate-related collapses in the pattern of cyclical abundance of rodents, as predators target alternative prey in the absence of their main food (Quakenbush et al. 2004, Iles et al. 2013).

Habitat loss also occurs through prospecting for, and the exploitation of, natural resources such as oil and gas (Kear 2005). The increasing traffic of tankers carrying oil from Arctic areas imposes the risk of contamination following spills (Kear 2005). There are concerns in Alaska that a road-building project approved by the United States Congress in 2009 may impact the species (Morse 2009). Disease and water pollution may impact eiders in their wintering area in south-west Alaska. It is not currently clear which of these many factors is driving the overall decline (K. Laing in litt. 2004, Žydelis et al. 2006).

Over-hunting in Siberia and in other breeding areas may be impacting Steller's Eider populations while large numbers may be taken during the spring migration, though data on levels are poor (Pihl 1997). Subsistence hunting has been ongoing in Alaska since the late 19th century and may have affected breeding populations in this area (Fredrickson 2001). Studies at Barrow indicate that the historical and ongoing use of lead shot in hunting causes lead poisoning, despite being made illegal in a nationwide ban in 1991 (Morse 2009). Eiders breeding in Russia are also subject to human subsistence harvest and exposure to lead shot, where declines in the number of wintering birds on Bering Island, Russia appear to be greater on the west coast near the only village on the island; new protective zones are being proposed there (Y. Artukhin per K. Laing in litt. 2007). Males are subject to particular hunting pressure as they arrive on moulting grounds before females (Morse 2009).

Another threat is mortality resulting from bycatch in gillnet fisheries, which has been documented in Lithuanian waters (Dagys and Žydelis 2002) and resource competition from shellfisheries. Redistribution is likely to have reduced bycatch in some areas, but the foraging ecology of the species puts it at risk from bycatch where they overlap with fishing fleets, for example in Estonia (Skov et al. 2011, Žydelis et al. 2013).

Nest predation by mammalian and avian predators such as Arctic Fox Vulpes lagopus, Snowy Owl Nyctea scandiaca and Pomarine Jaeger Stercorarius pomarinus appears to be a threat on Alaskan breeding grounds. No nesting was observed near Barrow between 2001 and 2004, but nesting has since occurred with some success following the inception of fox control in 2005 (Safine 2011). Increasing human habitation of Arctic regions has increased the range and numbers of Ravens Corvus corax and some large gulls, leading to a greater predation pressures (Kear 2005).

Conservation actions

Conservation Actions Underway
CMS Appendix I and II. EU Birds Directive Annex I. Bern Convention Appendix II. A European action plan was published in 2000, and the US Fish and Wildlife Service successfully proposed the critical habitat designation of 4,528 km2 of coastal habitat for the conservation of this species (Anon. 2001). It is a protected species in both Russia and the U.S.A.. Work has begun in Russia to conduct waterfowl population and subsistence harvest surveys (K. Laing in litt. 2004). A captive breeding and research programme (including 50 years of banding data) is underway in Alaska (Alaska SeaLife Center 2004). New protective zones are being proposed around wintering sites on Bearing Island (Y. Artukhin per K. Laing in litt. 2007), including additional protected zones of the Komandorskiy Reserve (Belobrov and Artukhin 2008).

Conservation Actions Proposed
Survey breeding and wintering grounds (particularly surrounding the Kola Peninsula, Russia) to determine population size and trends. Determine causes of current declines. Work to mitigate threats such as lead poisoning. Ensure subsistence harvest is sustainable. Support and extend the captive breeding programme to support future reintroductions and supplementation.

Identification

43-47 cm. Smallish marine duck with squarish head and angular bill; breeding plumage male unmistakable (in eclipse blackish with white secondary coverts); 1st winter male brown with faint suggestion of male head markings - blackish throat and collar; female red-brown with blue tertials (except 1st winter when brown) and whitish inner webs. Most female-type plumages show pale eye ring. Flight fast with rapid beats; male shows white forewing and trailing edge, female has thin white wing bar and trailing edge. Similar spp. Best told from other Eiders in non adult male plumage by shape and size supported by various plumage features described above. Hints Occurs in tight flocks which dive simultaneously, search amongst other eider species away from main range.

Acknowledgements

Text account compilers
Harding, M., Anderson, O., Hermes, C., Martin, R., Moreno, R., Palmer-Newton, A., Stuart, A., Temple, H., Butchart, S., Ashpole, J, Crawford, R., Derhé, M., Ekstrom, J., Fjagesund, T., Gilroy, J.

Contributors
Stehn, H., Laing, K., Solovyeva, D., Martin, K., Stehn, R., Burfield, I., Pihl, S., Dau, C., Artukhin, Y.


Recommended citation
BirdLife International (2020) Species factsheet: Polysticta stelleri. Downloaded from http://www.birdlife.org on 09/08/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 09/08/2020.