Justification of Red List Category
This species has a small population and is suspected to be undergoing a moderately rapid population decline owing to unsustainable subsistence harvest. However, accurate data are lacking and further surveys need to be conducted to quantify the current rate of harvest. Therefore, precautionarily, the species is listed as Near Threatened.
The global population has been estimated at 16,000-32,000 individuals.
Population trends have not been quantified. However, the total of c.1,000 individuals harvested in the Bering Sea region in 2007 indicates that subsistence harvest may be causing a population decline (M. Kirchhoff in litt. 2010). Furthermore, there is evidence to suggest that the breeding range of the species has declined in the west and east of Russia (K. Laing in litt. 2008). As such, a decline of 1-19% over the past 29 years (three generations) is precautionarily suspected, although surveys are required to confirm that such declines are currently occurring.
This species breeds in the Arctic in Russia, Alaska (U.S.A.) and Canada, and winters at sea mainly off the coasts of Norway (>1,500 individuals [Bell and Håland 2008]), western North America, and the eastern coast of Asia, including the coasts of Japan, North Korea, South Korea, and China (del Hoyo et al. 1992, U.S. Fish and Wildlife Service 2009). The population is thought to number 16,000-32,000 individuals, with 3,000-4,000 in Alaska, 20,000 in Canada and 8,000 in Russia (U.S. Fish and Wildlife Service 2009), although the breeding range in Russia has possibly contracted (K. Laing in litt. 2008). The westernmost breeding site in Russia is the south-western coast of Novaya Zemlya archipelago; the most dense (1.8 bp/10 sq km) and stable population is thought to be on Chukotka Peninsula; and the northernmost record is from the Upper Taimyra river mouth, Central Taimyr (see Håland 2008). The minimum European population in winter is estimated at 1,000 individuals (BirdLife International 2015).
Behaviour This species is fully migratory (del Hoyo et al. 1992). It breeds from early June (largely depending upon the timing of the spring thaw) in solitary pairs, after which it travels southwards and towards the coast to its wintering grounds, where it is present between October and May (del Hoyo et al. 1992, Snow and Perrins 1998). Outside of the breeding season the species occurs singly, in pairs or in small groups (Snow and Perrins 1998).
Habitat Breeding The species may breed on low-lying Arctic coasts and estuaries, but is more common on freshwater pools, lakes or rivers in the Arctic tundra, showing a preference for deep, clear lakes with stony or sandy substrates where water levels do not fluctuate (Flint et al. 1984, North and Ryan 1989, del Hoyo et al. 1992, Earnst et al. 2006). Optimum habitats include lakes where the water does not completely freeze, which have dependable supplies of fish and which have highly convoluted shorelines and aquatic vegetation providing habitats for fish and sites for nesting and brood rearing (Earnst et al. 2006). The species generally avoids forested areas, but may fly long distances to feed away from breeding waters (del Hoyo et al. 1992, Snow and Perrins 1998). Non-breeding Outside of the breeding season, the species inhabits inshore waters, fjords with muddy substrates and inlets along sheltered coasts, generally avoiding ice-covered waters (del Hoyo et al. 1992, Snow and Perrins 1998, Byrkjedal et al. 2000).
Diet Its diet is little known, but may consist predominantly of fish (e.g. Coregonus and Pungitius species, cottidae, Microgadus proximus and Gadus morhua) as well as crustaceans, molluscs and marine annelids (del Hoyo et al. 1992).
Breeding site The nest is a small depression in a mound of plant matter or turf constructed on dry land 1 m away from the edge of water, usually on the shores of lakes with deep, clear water and stony or sandy substrates in sites providing good visibility over the surrounding land and water (Flint et al. 1984, North and Ryan 1989, del Hoyo et al. 1992, Earnst et al. 2006).
The Yellow-billed Loon is harvested for subsistence in Alaska, and a record of c.1,000 individuals taken in the Bering Sea region in 2007 indicates that this may pose the greatest threat to the species (U.S. Fish and Wildlife Service 2009, M. Kirchhoff in litt. 2010). More recently, however, other approaches to quantify loon harvest have come up with figures of 5 birds annually in 2011 and 2012 (Naves and Zeller 2017). Although this species is vulnerable to oil spills, its very large range means it is unlikely that a large proportion of the global population will be affected by any single event. Mercury or other heavy metal contamination pose a potential threat, particularly for birds wintering on the Asian side of the Pacific where feather and egg mercury concentrations considerably above background levels have been recorded (Evers et al. 2014). There is some competition with fisheries for food, however, this only impacts a small percentage of the global population. Threats are exacerbated by a low reproductive rate and very specific breeding habitat requirements (K. Laing in litt. 2008, U.S. Fish and Wildlife Service 2009).
Conservation Actions Underway
Western Palearctic population is CMS Appendix II. In 2006, the U.S. Fish and Wildlife Service, working with a variety of native, state and federal partners, developed a conservation agreement to protect the species in northern and western Alaska, with an aim to eliminate or reduce current or potential threats (U.S. Fish and Wildlife Service 2009). The species is closely monitored and a 2013 report about subsistence harvest of loons now ameliorates concerns and suggest that the exceptional harvest estimate from 2007 was biased.
Text account compilers
Martin, R., Moreno, R., Stuart, A., Ashpole, J, Butchart, S., Calvert, R., Ekstrom, J., Anderson, O., Fjagesund, T., Hermes, C., Malpas, L.
Schmutz, J., Laing, K., Kirchhoff, M.
BirdLife International (2020) Species factsheet: Gavia adamsii. Downloaded from http://www.birdlife.org on 02/04/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 02/04/2020.