Clangula hyemalis 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Anseriformes Anatidae

Scientific Name: Clangula hyemalis
Species Authority: (Linnaeus, 1758)
Regional Assessments:
Common Name(s):
English Long-tailed Duck
Spanish Pato havelda
Taxonomic Source(s): del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Lynx Edicions BirdLife International, Barcelona, Spain and Cambridge, UK.

Assessment Information [top]

Red List Category & Criteria: Vulnerable A4bce ver 3.1
Year Published: 2016
Date Assessed: 2016-10-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Contributor(s): Bellebaum, J., Below, A., Bianki, V., Bowman, T., Ellermaa, M., Fefelov, I., Grishanov, G., Hario, M., Hearn, R., Kharitonov, S., Kharitonova, I., Kondratyev, A., Kontiokorpi, J., Lehikoinen, A., Lehikoinen, E., Lehtiniemi, T., Mikkola-Roos, M., Mineev, O., Mineev, Y., Nilsson, L., Pessa, J., Pihl, S., Rajasarkka, A., Solovyeva, D., Tiainen, J. & Valkama, J.
Facilitator/Compiler(s): Ashpole, J, Butchart, S., Calvert, R., Ekstrom, J., Malpas, L., Moreno, R., Taylor, J.
This species has been listed as Vulnerable because of an apparent severe decline detected in the wintering population in the Baltic Sea between the early 1990s and late 2000s. This rate of decline implies that the global population will undergo at least a ≥30 decline over three generations (1993-2020), even when factoring-in uncertainty regarding the sizes and trends of other populations. Improved knowledge regarding populations outside the Baltic Sea might lead to the species being uplisted to Endangered if the overall rate of decline can be confidently shown to be very rapid.

Previously published Red List assessments:

Geographic Range [top]

Range Description:This species has a circumpolar range, breeding on the Arctic coasts of North America (Canada, Alaska, U.S.A. and Greenland), Europe (Iceland and Norway), and Asia (Russia). It winters at sea further south, as far as the United Kingdom, South Carolina and Washington in the United States, Korea on the Asian Pacific coast, and other areas including the Black Sea and Caspian Sea (del Hoyo et al. 1992). According to monitoring data from the Baltic Sea, where the western Siberian and northern European populations winter, the population there has declined significantly since the early 1990s at least (Hario et al. 2009, Ellermaa et al. 2010, Nilsson and Månsson 2010, Skov et al. 2011). An estimated total of c.4,272,000 individuals was counted there in 1992-1993, falling to c.1,486,000 individuals in 2007-2009, which suggests that a decline of c.65% has occurred over a period of 16 years (Skov et al. 2011). Research on the tundra of eastern European Russia since 1973 suggests that a steep decline may have occurred there (Y. and O. Mineev in litt. 2012). There is no evidence to suggest that the geographical distribution of this population has shifted sufficiently to account for this decline (Skov et al. 2011, L. Nilsson in litt. 2011, J. Bellebaum in litt. 2012, M. Ellermaa in litt. 2012), though small increases in wintering numbers have been recorded in Finland. The estimation of a real and severe decline is supported by data from migration bottlenecks in the Gulf of Finland where the numbers observed on migration have fallen dramatically since the early 1990s at least (A. Lehikoinen et al. in litt. 2012). North America holds the second largest population (c.1 million birds [Delany and Scott 2006]). Although Christmas Bird Count (CBC) data indicate an annual population change of -1.9% between 1965 and 2005, across c.70% of the species’s range in North America (Butcher and Niven 2007); however, the reliability of CBC data for monitoring this species has been questioned owing to the species's tendency to winter off-shore (T. Bowman in litt. 2012). There are conflicting results from regional surveys. Indices of abundance obtained during the North American Breeding Waterfowl Survey indicate a steady long-term downward trend between the 1970s and early 1990s, and a stable population since. However, this species is especially poorly monitored because its breeding distribution is largely outside the area covered by breeding waterfowl surveys, and because of its offshore distribution during winter and the lack of comprehensive winter surveys (T. Bowman in litt. 2012). No trend data are available for the third largest population (c.500,000–1,000,000 birds [Delany and Scott 2006]), which breeds in eastern Siberia and winters off eastern Asia. The fourth and smallest population (c.100,000–150,000 birds [Wetlands International 2016]), which breeds in Greenland and Iceland and winters in the north Atlantic, is poorly monitored and trends are uncertain, although it may have been stable until the 1990s (Delany and Scott 2006). 

Countries occurrence:
Austria; Azerbaijan; Belarus; Belgium; Bulgaria; Canada; China; Czech Republic; Denmark; Estonia; Faroe Islands; Finland; France; Germany; Greece; Greenland; Hungary; Iceland; India; Iran, Islamic Republic of; Ireland; Italy; Japan; Kazakhstan; Korea, Democratic People's Republic of; Korea, Republic of; Kyrgyzstan; Latvia; Lithuania; Macedonia, the former Yugoslav Republic of; Mexico; Montenegro; Nepal; Netherlands; Norway; Pakistan; Poland; Romania; Russian Federation; Saint Pierre and Miquelon; Serbia (Serbia); Slovakia; Slovenia; Spain; Svalbard and Jan Mayen; Sweden; Switzerland; Turkmenistan; Ukraine; United Kingdom; United States
Armenia (Armenia); Bermuda; Bosnia and Herzegovina; Croatia; Israel; Jordan; Luxembourg; Portugal; Turkey
Additional data:
Continuing decline in area of occupancy (AOO):Unknown
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:60100000
Continuing decline in extent of occurrence (EOO):UnknownExtreme fluctuations in extent of occurrence (EOO):No
Continuing decline in number of locations:Unknown
Extreme fluctuations in the number of locations:No
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:The global population is estimated to number 3,200,000 to 3,750,000 (Wetlands International 2016).

Trend Justification:  Surveys of the wintering population in the Baltic sea indicate that the species has undergone a precipitous decline there, from c.4,272,000 individuals in 1992-1993 to c.1,486,000 individuals in 2007-2009 (Skov et al. 2011). There is considerable uncertainty over the trends of smaller populations in Europe outside the Baltic sea (300,000 individuals [Delany and Scott 2006]), in Greenland and Iceland (c.150,000-1,200,000 individuals [BirdLife International]), and East Siberia (500,000-1,000,000 [Delany and Scott 2006]), and North America (c.1,000,000 individuals [Delany and Scott 2006]), rendering the estimation of its global trend very difficult. The European wintering population is estimated to be declining by 30-49% (BirdLife International 2015). However, the overall rate of decline is likely to approach 50% over three generations (27 years), from 1993 until 2020. The population size in winter is estimated to be decreasing by 30-49% in 27 years (three generations).

Current Population Trend:Decreasing
Additional data:
Continuing decline of mature individuals:Yes
Extreme fluctuations:NoPopulation severely fragmented:No
Continuing decline in subpopulations:Unknown
Extreme fluctuations in subpopulations:NoAll individuals in one subpopulation:No

Habitat and Ecology [top]

Habitat and Ecology:Behaviour This species is fully migratory (del Hoyo et al. 1992) although its movements are poorly understood (Scott and Rose 1996). It breeds from late-May onwards (Madge and Burn 1988) in single pairs or loose groups (del Hoyo et al. 1992, Kear 2005b), the males leaving the females soon after the start of incubation (Madge and Burn 1988) (between late-June and early-September) to gather in small flocks for a flightless moulting period (Scott and Rose 1996). Some populations undergo extensive moult migrations of up to 1,000 km, while others moult on waters near the breeding grounds (Madge and Burn 1988). Females moult between early-August and early-October on the breeding grounds (Scott and Rose 1996), often abandoning their young at the start of the moult (the ducklings then gather into large parentless groups) (Johnsgard 1978). The southward autumn migration occurs from September to October after the post-breeding moult (Scott and Rose 1996) and non-breeders may oversummer in the wintering areas (Madge and Burn 1988). Outside of the breeding season the species is highly gregarious (Johnsgard 1978), in winter gathering into large aggregations of perhaps several tens of thousands of individuals to roost or to feed in inshore and offshore waters (del Hoyo et al. 1992). The species regularly dives to depths of 3-10 m when foraging (maximum depth 50-60 m) (Kear 2005b) and is diurnal (Kear 2005b). Habitat Breeding The species breeds on marshy grass tundra in the high Arctic (Flint et al. 1984, del Hoyo et al. 1992), especially where habitat mosaics are formed by hummocks and ridges together with moist depressions (Snow and Perrins 1998), freshwater lakes (del Hoyo et al. 1992, Kear 2005b), bogs (del Hoyo et al. 1992), slow rivers (Madge and Burn 1988, del Hoyo et al. 1992) or pools of standing water (Snow and Perrins 1998). It generally avoids wooded tundra (Johnsgard 1978, Snow and Perrins 1998) but is common among willows or dwarf birch in the arctic-alpine zone (Scandinavia) (Snow and Perrins 1998). The species also breeds on small rocky islands off mainland Arctic coasts and on larger offshore islands, using promontories, deltas (Snow and Perrins 1998), coastal inlets (Madge and Burn 1988, del Hoyo et al. 1992) and islets in fjords (Greenland) (Snow and Perrins 1998). Non-breeding The species winters at sea, generally far offshore (del Hoyo et al. 1992) in waters 10-35 m deep (Scott and Rose 1996), as well as in saline, brackish or fresh estuarine waters (Johnsgard 1978), brackish lagoons (del Hoyo et al. 1992), and inland (very rarely) on large, deep freshwater lakes (del Hoyo et al. 1992). Diet The species shows a preference for marine foods during both the breeding and non-breeding seasons (Johnsgard 1978), its diet consisting predominantly of animal matter (Snow and Perrins 1998) such as crustaceans (del Hoyo et al. 1992) (e.g. amphipods [Kear 2005b] and cladocerans [Johnsgard 1978]), molluscs, other marine invertebrates (e.g. echinoderms, worms) and fish (del Hoyo et al. 1992). The species also takes freshwater insects and insect larvae (del Hoyo et al. 1992) as well as plant material such as algae, grasses, and the seeds and fruits of tundra plants (del Hoyo et al. 1992). Breeding site The nest is a natural depression on dry ground positioned in the open, amongst vegetation (del Hoyo et al. 1992), partially hidden by overhanging boulders (Madge and Burn 1988) or under low shrubs (Johnsgard 1978) (e.g. willows or dwarf birch) (Flint et al. 1984) usually close to water (Madge and Burn 1988). Although it is not a colonial species some pairs may nest in loose groups, and the species may also nest in association with Arctic Terns (Kear 2005b).

Systems:Terrestrial; Freshwater; Marine
Continuing decline in area, extent and/or quality of habitat:Unknown
Generation Length (years):9
Movement patterns:Full Migrant
Congregatory:Congregatory (and dispersive)

Threats [top]

Major Threat(s): The species is threatened by wetland habitat degradation and loss from petroleum pollution, wetland drainage and peat-extraction (Grishanov 2006). It is also threatened with direct mortality from oil pollution (Gorski et al. 1977, del Hoyo et al. 1992, Kirby et al. 1993), drowning through entanglement in fishing nets (del Hoyo et al. 1992, Kirby et al. 1993) and from hunting on migration routes over certain regions of the Arctic (del Hoyo et al. 1992). The species has previously suffered heavy losses from an outbreak of avian cholera (Friend 2006) and is susceptible to avian influenza (Melville and Shortridge 2006) so may be threatened by future outbreaks of these diseases. There is evidence that the species is experiencing low reproductive success on its Arctic breeding grounds. The results of autumn migration monitoring at various Baltic sites show that juveniles now represent a very low proportion of the population (e.g. Hario et al. 2009, Ellermaa et al. 2010), indicating that insufficient young are being raised to compensate for adult mortality. The breeding success of this (and other) species seems to have declined since the mid-1990s, when the formerly distinctive 3-4 year cycle in the abundance of Arctic rodents collapsed, probably due to climate change. With fewer rodents around, Arctic predators now take a heavier toll on breeding birds every year, instead of only once every 3-4 years. Although the main reason for low breeding productivity seems to be likely connected mainly with skipped breeding, rather than with increased predation pressure, possibly owing to worsened female body condition (A. Kondratyev in litt. 2012). A decline in breeding productivity is supported by unpublished data on the age ratio of gillnet victims in the southern Baltic, which suggest a decline in breeding success by c.75% from prior to 1990 until c. 2000 (J. Bellebaum in litt. 2012). Drastic declines on the tundra of eastern European Russia since 1973 are thought to be connected to the natural cycles of the species, pollution from oil and gas extractions, and pollution from the deposition of nuclear and chemical waste in northern seas (Y. and O. Mineev in litt. 2012). In 2006-2007, on the Hatpudirskaya bay coast (Barents Sea), several thousand dead C. hyemalis were found washed-up on beaches (Y. and O. Mineev in litt. 2012). Utilisation The species is hunted for sport in several countries including Denmark (Bregnballe et al. 2006) and the USA.

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
CMS Appendix II. EU Birds Directive Annex II. Some of the species's habitat is protected. Efforts are on-going to monitor populations of this species in many parts of its range.

Conservation Actions Proposed
Conduct surveys to monitor the least-known populations in East Asia, improve monitoring in North America, and continue to assess trends in Europe. Carry out research to identify the causes of the decline in the Baltic Sea. React to improved knowledge of threats to the species by implementing actions to mitigate their impacts. Study the causes of reduced breeding productivity.

Citation: BirdLife International. 2016. Clangula hyemalis. The IUCN Red List of Threatened Species 2016: e.T22680427A84475073. . Downloaded on 22 January 2017.
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