Data Zone
Justification of Red List category
Rapid declines at one site, and a suite of threats that could impact the population as a whole suggest that the species is overall declining at a rate that is at least moderately rapid. Thus the species is listed here as Near Threatened, but future surveys could show that the species is declining at an even greater rate.
Population justification
Wetlands International (2020) estimate the global population to number 360,000-400,000 individuals, in line with the 2010 estimate based on aerial surveys of winter flocks in the Bering Sea of 369,122 individuals, rounded here to 370,000 individuals (Larned et al. 2012). This equates to 246,081 mature individuals, rounded here to 250,000 mature individuals, as estimated by Partners in Flight (2019).
Trend justification
Previously, the Russian and Alaskan populations were of a roughly similar size, with the Yukon-Kuskokwim Delta holding on average 50,000 pairs (see Dau and Kistchinski 1977). However, the population in the Yukon-Kuskokwim Delta underwent a massive crash in the late 20th Century, such that by 1992 only 1,721 pairs remained (Stehn et al. 1993). The population in this area has since slightly recovered and potentially stabilised (Sea Duck Joint Venture 2016, Fischer et al. 2017, Swaim 2017) and by 2017, the population was estimated to number 6,956 individuals (Wilson et al. 2018). Russia is now however, considered to hold 90% of the breeding population (Warnock 2017, D. Solovyeva in litt. 2018).
In Arctic Alaska the population is not thought to have undergone such severe declines as in the Yukon-Kuskokwim Delta, though clear data about population trends were lacking due to the timing of surveys potentially missing many individuals who leave the breeding grounds early (Stehn et al. 2013). More recent surveys have shown the species to potentially be declining there, though these declines appear to be very slight, and not statistically significant (Stehn et al. 2013). There has not been as much survey work conducted throughout the Russian population and so trends have been difficult to determine there. However, recent surveys from Ayopechan Island have shown the population there to be decreasing rapidly (Solovyeva et al. 2017b).
For past declines, we would have to look at the period since the early 1990s, and so the rapid declines in the Yukon-Kuskokwim Delta population would not be included. Instead, over this time period there has been an increase in this population (although recent evidence suggests an overestimation of the recent population size and that the population increase and recovery may not have been as strong as first assumed [Lewis et al. 2019]), and a non-significant decline in the other Alaskan population. Amundson et al. (2019) considered Spectacled Eider populations to be stable throughout much of their core range on the North Slope of Alaska, increasing between Admiralty Bay and Teshepuk Lake but declining along the Alaskan coast south of Point Lay. However, if Ayopechan Island is representative for the whole of the Russian range then the overall population trend could be a rapid decline. Declines there have been at a rate of 8% per annum between 2009 and 2016; such declines continued through to 2019 (Solovyeva et al. 2017b, D. Solovyeva in litt. 2020), which could mean that the overall population trend in the past 3 generations was a decline c.39% (assuming that overall the other populations are stable, and the population in Russia returned to stability after 2016). If this is brought forward to look at potential current, ongoing trends, it could be that the species is undergoing a decline that could end up as high as c.79% over 3 generations over the period 2009-2035 (assuming stable Alaskan populations, and declines continue at the same rate in Russia). However, this does depend on the assumption that trends on Ayopechan Island are representative of the entire Russian range, which contains the vast majority of the global population. Recent evidence from the Chaun Delta, Chukotka, Russia, evidenced a x3.7 decline in nest density between 2011-2019 with a x4.1 decline in the number of observed individuals during the same period, further supporting a declining trend in the Russian population (D. Solovyeva in litt. 2020).
Solovyeva et al. (2017a) provide evidence that overall population trends may depend more on conditions at the over-wintering area rather than breeding-site-specific threats, so it is plausible that these trends could be affecting the whole of the Russian population. The first surveys of the wintering flocks in the Bering Sea since 2009-2010 were planned for March 2019 (K. Martin in litt. 2018), and these will likely be the best avenue to get a quantification of the overall population trend, as it is thought that the entire global population may over-winter in this area. Before this information becomes available though, it is tentatively suspected that the population is undergoing a moderately rapid decline.
This species breeds along the coasts of north-east Siberia, Russia, east from the Yana Delta to Cape Schmidt, and also along the Beaufort Sea coast of Alaska's North Slope and the Yukon-Kuskokwim Delta, Alaska, USA. 90% of the breeding population is thought to inhabit the Russian range with just 5% of the population residing in the northern Alaskan and Yukon-Kuskokwim Delta ranges respectively (Goldman et al. 2017). Its wintering grounds have only recently been discovered in an otherwise unbroken sea of ice halfway between St Lawrence and St Matthew Islands in the Bering sea (Balogh 1996, Petersen 1996, Solovyeva 2011).
This species breeds on small lakes, pools, bogs and streams of the tundra. It mainly feeds on molluscs but will also take crustaceans, with a more varied diet in summer including insects, arachnids, berries and seeds. It feeds by diving, and will pluck or dabble on the surface. Breeding begins in May or June in single pairs or loose groups (del Hoyo et al. 1992).
Climate change potentially represents the greatest threat to the species. Warming and sea ice retreat poses an ongoing and future threat to the species’ habitat as sea ice provides an important resting platform when not foraging (Lovvorn et al. 2009). Reductions in ice habitat are predicted to result in large decreases in the area of viable habitat, even in the absence of other impacts such as shifts in food availability (Lovvorn et al. 2009). Such habitat shifts have been seen in almost one third of winters between 1998 and 2011, denying access to preferred foraging locations and forcing prey switching, resulting in adult body fat being one third lower than in winters with access to these resources (Lovvorn et al. 2014). A recent modelling study by Christie et al. (2018) reveals that under an RCP 8.5 scenario, the species's abundance will likely increase through to 2040 before declining rapidly through to near extirpation in the late 21st century as the Bering Sea becomes ice-free. There appears to be no difference in mean survival between widely separated breeding areas, indicating that survival is mainly a function of wintering conditions (Solovyeva et al. 2017). Wetlands provide important breeding grounds for the species, and remote sensing and imaging has shown shrinkage and disappearance of lakes and ponds in Alaska and Siberia (Smith et al. 2005, Riordan et al. 2006), while the alteration of habitats through coastal erosion, inundation and salinization from storm surges, thawing permafrost, and sedimentation changes due to sea level rise and increased river discharge could change the suitability of current nesting areas (U.S. Fish and Wildlife Service 2010). However, no link between wetland loss and population decline has been made for this species yet. Nevertheless, climate change is predicted to cause dramatic habitat changes in the Arctic region, with unknown impacts on the long-term survival of the species (Fox et al. 2015). Climate change has also been held responsible for severely reducing the Eiders’ benthic prey, likely due to ocean acidification (e.g. molluscs which form a large part of Eider diet) (Steinacher et al. 2009, U.S. Fish and Wildlife Service 2010, Carboneras and Kirwan 2017); Macoma calcarea, a key prey of the Spectacled Eider, is evidenced to be decreasing in abundance throughout sites in the Bering Sea, influencing the Eider's winter foraging (Goethel et al. 2018).
Direct persecution poses another major threat to the species, with 10s to 100s of individuals harvested in Alaska and 10,000-14,000 in Russia per annum (U.S. Fish and Wildlife Service 2010). This represents around 5% annual mortality, based on a population of 330,000 (Carboneras and Kirwan 2017). Pollution also threatens this species with lethal and sub-lethal levels of lead poisoning from ingested lead shot found in the Yukon-Kuskokwim Delta breeding population, with levels high enough to influence regional subpopulation dynamics (Flint et al. 2016, Sea Duck Joint Venture 2016). Exposure to lead reduced estimated survival from 0.78 to 0.44 (U.S. Fish and Wildlife Service 2010), while the survival of females exposed to lead was 0.34 lower than that of those with blood lead levels at or below background levels (Grand et al. 1998). Lead levels exceeding typical exposure thresholds were found in 30.7% of females in the Chaun Delta, Russia between 2003-2010; however, only 8.8% exhibited levels above the critical threshold (D. Solovyeva in litt. 2012, 2020). Lead shot is likely not a serious threat to Siberian populations due to the low human density in the breeding range (D. Solovyeva in litt. 2020).
Oil spills occur in the species range, and although infrequent, represent a significant risk to the population (U.S. Fish and Wildlife Service 2010). Oil and gas development on the central coast of Alaska's Arctic Coastal Plain has altered nesting habitat, causing potential threats from oil contamination, off-road vehicle use, wetland filling as well as the indirect effects of human disturbance (U.S. Fish and Wildlife Service 2010). However, the development related to the petroleum industry is not regarded a significant threat to the species as only a small proportion of the species’s range is within or near developed areas. The risk to eiders from collisions and disturbance resulting from industrial activities and interaction with shipping lanes linked to oil and gas development is thought to be low and is unlikely to have population-level effects (U.S. Fish and Wildlife Service 2010). The species is susceptible to avian influenza, but at present, the disease appears not to have any significant effects on the population. Seroprevalence of avian influenza in Spectacled Eider is approximately 90% (Wilson et al. 2013), but less than 5% tested positive for the virus (Ip et al. 2008).
Arctic Foxes Vulpes lagopus are present in the species’s range and may contribute to mortality through predation. Density of wolverine and now brown bear appear to have increased in low Arctic tundra as a result of climate change impacts (Solovyeva 2016). Modelling of breeding success indicates that predation is likely to be driving reductions in productivity, although factors operating over winter are likely to be the main drivers of observed declines across the range (Solovyeva et al. 2017a). Changes in the species community composition may be also having an effect, with a decline in Sabine’s Gull Xema sabini and Arctic Tern Sterna paradise (which provide nest protection) and an increase in mammalian predators and Vega Gull Larus smithsonianus vegae potentially leading to reduced breeding success (see Solovyeva and Zelenskaya 2016, Solovyeva et al. 2017b). It is possible that these community changes are a result of climate change (D. Solovyeva in litt. 2018).
Conservation Actions Underway
In 2000 the US Fish and Wildlife Service designated 62,386 km² of critical coastal habitat for the conservation of this species (Anon. 2001). Winter surveys are planned to get a revised population size estimate, and a better idea of the magnitude of overall trends (K. Martin in litt. 2018).
Conservation Actions Proposed
Continue regular monitoring of the winter population, as this is the easiest way to monitor overall trends. Conduct research across wider areas of the Russian population, where possible. Assess the amount of hunting pressure on the species in Russia.
Text account compilers
Hermes, C., Everest, J., Martin, R.
Contributors
Arendarczyk, B., Benstead, P., Butchart, S., Calvert, R., Ekstrom, J., Fox, A., Harding, M., Martin, K., Palmer-Newton, A., Solovyeva, D., Westrip, J.R.S., Stuart, A. & Fjagesund, T.
Recommended citation
BirdLife International (2024) Species factsheet: Spectacled Eider Somateria fischeri. Downloaded from
https://datazone.birdlife.org/species/factsheet/spectacled-eider-somateria-fischeri on 22/11/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 22/11/2024.