This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is extremely large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
AERC TAC. 2003. AERC TAC Checklist of bird taxa occurring in Western Palearctic region, 15th Draft. Available at: #http://www.aerc.eu/DOCS/Bird_taxa_of _the_WP15.xls#.
Cramp, S.; Perrins, C. M. 1977-1994. Handbook of the birds of Europe, the Middle East and Africa. The birds of the western Palearctic. Oxford University Press, Oxford.
del Hoyo, J.; Collar, N. J.; Christie, D. A.; Elliott, A.; Fishpool, L. D. C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Barcelona, Spain and Cambridge UK: Lynx Edicions and BirdLife International.
The global population is estimated to number c.2,200,000-2,500,000 individuals (Wetlands International 2006), while national population sizes have been estimated at c.10,000 individuals on migration and <c.10,000 wintering individuals in Korea and <c.100 breeding pairs and c.1,000 wintering individuals in Japan (Brazil 2009).Trend justification
The overall population trend is decreasing, although some populations may be stable and others have unknown trends (Wetlands International 2006).EcologyBehaviour
Northern populations of this species are highly migratory (Scott and Rose 1996, Snow and Perrins 1998), with those breeding in the milder parts of western or southern Europe (Snow and Perrins 1998) being sedentary (del Hoyo et al.
1992, Scott and Rose 1996, Snow and Perrins 1998) or only making short-distance dispersal movements (del Hoyo et al.
1992, Scott and Rose 1996, Snow and Perrins 1998) governed by harsh weather conditions (Scott and Rose 1996). The spring migration may occur as early as February in mild winters, with the main migration occurring from March to early-April (Scott and Rose 1996). The breeding grounds are reoccupied from the early-March (in the south) to early May (in Siberia) (Scott and Rose 1996) with breeding starting from April-May (del Hoyo et al.
1992). The species mainly moults on the breeding grounds before the autumn migration, becoming flightless for a period of 3-4 weeks (Scott and Rose 1996). The autumn migration to wintering grounds peaks between late-September and November (Scott and Rose 1996), females migrating slightly later than the males (which results in a segregation of the sexes in the wintering range: males further north and females further south) (Snow and Perrins 1998). The species breeds in single pairs or loose groups (del Hoyo et al.
1992) and travels in small parties on passage (Snow and Perrins 1998), sometimes gathering in flocks of many thousands during the post-breeding moult period (Snow and Perrins 1998). During the winter it becomes highly gregarious, gathering in flocks of many thousands of individuals (Madge and Burn 1988, Scott and Rose 1996, Snow and Perrins 1998). The species can be crepuscular in the winter, and often feeds by night (Kear 2005b) by bottom-feeding and diving (Snow and Perrins 1998) (most foraging being done at depths of 1-3 m) (Johnsgard 1978). Habitat
The species requires extensive areas of nutrient-rich open water less than 6 m deep (Scott and Rose 1996) that is uncluttered with floating vegetation (Snow and Perrins 1998) but has abundant submerged macrophytes (Madge and Burn 1988, Kear 2005b), surrounding emergent (Madge and Burn 1988) vegetation and/or animal food (e.g. Chironomid larvae) (Kear 2005b). Breeding
In its breeding range the species inhabits base-rich (e.g. saline, brackish or soda) lakes (Kear 2005b), eutrophic freshwater lakes, well-vegetated freshwater or brackish (Johnsgard 1978) marshes with areas of open water, swamps (del Hoyo et al.
1992, Scott and Rose 1996) and slow-flowing rivers (Madge and Burn 1988, del Hoyo et al.
1992, Scott and Rose 1996). Although it shows a strong preference for inland wetlands (Snow and Perrins 1998), the species will shift to coastal habitats such as sheltered coastal bays (Kear 2005b) when driven by frost or other compelling factors (Snow and Perrins 1998). Non-breeding
During the winter the species frequents similar habitats to those it breeds in, including large lakes (Brown et al.
1982, del Hoyo et al.
1992, Scott and Rose 1996), slow-flowing rivers (Madge and Burn 1988, del Hoyo et al.
1992, Scott and Rose 1996), reservoirs (Brown et al.
1982, Madge and Burn 1988, del Hoyo et al.
1992, Scott and Rose 1996), brackish waters, marshes, weirs (Africa) (Brown et al.
1982) and flooded gravel pits (Fox et al.
1994). As in the breeding season, the species will shift to coastal habitats such as brackish lagoons (del Hoyo et al.
1992, Scott and Rose 1996), tidal estuaries (Madge and Burn 1988, del Hoyo et al.
1992, Scott and Rose 1996) and inshore waters (Madge and Burn 1988, Scott and Rose 1996) (where it associates with sewage outfalls) (Kear 2005b) when driven by frost or other compelling factors (Snow and Perrins 1998). Diet
The species is omnivorous, its diet consisting of seeds (del Hoyo et al.
1992, Kear 2005b), roots (del Hoyo et al.
1992), rhizomes (Kear 2005b) and the vegetative parts of grasses, sedges and aquatic plants (Johnsgard 1978, del Hoyo et al.
1992, Kear 2005b), as well as aquatic insects and larvae (del Hoyo et al.
1992) (e.g. midge and caddis fly larvae during the summer) (Johnsgard 1978), molluscs, crustaceans, worms (del Hoyo et al.
1992)(oligochaetes) (Marsden and Bellamy 2000), amphibians (del Hoyo et al.
1992) (e.g. frogs and tadpoles) (Brown et al.
1982) and small fish (del Hoyo et al.
1992). Breeding site
The nest is a depression (del Hoyo et al.
1992) or shallow cup (Kear 2005b) in a thick heap of vegetation (del Hoyo et al.
1992) positioned on the ground (Madge and Burn 1988, del Hoyo et al.
1992) (usually within 10 m of water) (Snow and Perrins 1998), in shallow water (Madge and Burn 1988, del Hoyo et al.
1992) (c.30 cm deep) (Johnsgard 1978), concealed in thick waterside vegetation (Madge and Burn 1988, del Hoyo et al.
1992) (e.g. reedbeds) (Johnsgard 1978), or on floating mats of reeds of other vegetation (Johnsgard 1978). In years of high water levels when there are few emergent reedbeds or floating mats the species may nest in sedge tussocks, in flooded fields, or under bushes on hummocks (Johnsgard 1978). Management information
In the Trebon Basin Biosphere Reserve, Czech Republic, it was found that artificial islands and wide strips of littoral vegetation are the most secure breeding habitats that can be created for the species (nest survival in littoral habitats was improved by reduced nest visibility, increased water depth, and increased distance from the nest to the habitat edge, and nest survival on islands was improved with increased distance to open water) (Albrecht et al.
2006). In the UK (Salford docks, Manchester) the species prefers to feed in waters heavily polluted with sewage that are devoid of aquatic vegetation but hold high densities of oligocheates and other pollution-tolerant organisms. The species may therefore suffer from plans to improve water quality in the docks (e.g. modernising sewage treatment systems and oxygenating water) (Marsden and Bellamy 2000). The cyclical removal of adult fish from an artificial waterbody (gravel pit) in the UK attracted nesting pairs to the area by causing an increase in invertebrate food availability and an increase in the growth of submerged aquatic macrophytes (Giles 1994). The removed fish (dead or alive) were sold to generate funds (Giles 1994).Threats
The species is threatened by disturbance from hunting (del Hoyo et al.
1992, Evans and Day 2002, Kear 2005b), water-based recreation (Fox et al.
1994, Kear 2005b) and from machinery noise from urban development (Marsden 2000). It is also threatened by habitat destruction (del Hoyo et al.
1992) on its wintering grounds due to eutrophication (partially as a result of nutrient run-off from agricultural land) (Kear 2005b). The species suffers from nest predation by American mink Mustela vison
in Poland (Bartoszewicz and Zalewski 2003), and adults are poisoned by ingesting lead shot (Spain) (Mateo et al
. 1998) and drowned in freshwater fishing nets with mesh sizes greater than 5 cm (China) (Quan et al.
2002). The species is also susceptible to avian influenza, so may be threatened by future outbreaks of the disease (Melville and Shortridge 2006). Utilisation
This species is hunted in Northern Island (Evans and Day 2002), Spain (Mateo et al
. 1998) and Italy (Sorrenti et al.
2006), and the eggs of this species used to be (and possibly still are) harvested in Iceland (Gudmundsson 1979). The species is also hunted for commercial and recreational purposes in Gilan Province, northern Iran (Balmaki and Barati 2006).
Albrecht, T.; HorÃ¡k, D.; Kreisinger, J.; Weidinger, K.; Klvana, P.; Michot, T. C. 2006. Factors Determining Pochard Nest Predation Along a Wetland Gradient. Journal of Wildlife Management 70(3): 784-791.
Balmaki, B.; Barati, A. 2006. Harvesting status of migratory waterfowl in northern Iran: a case study from Gilan Province. In: Boere, G.; Galbraith, C., Stroud, D. (ed.), Waterbirds around the world, pp. 868-869. The Stationary Office, Edinburgh, UK.
Bartoszewicz, M.; Zalewski, A. 2003. American mink, Mustela vison diet and predation on waterfowl in the Slonsk Reserve, western Poland. Folia Zoologica 52(3): 225-238.
Brazil, M. 2009. Birds of East Asia: eastern China, Taiwan, Korea, Japan, eastern Russia. Christopher Helm, London.
Brown, L. H.; Urban, E. K.; Newman, K. 1982. The birds of Africa vol I. Academic Press, London.
del Hoyo, J.; Elliot, A.; Sargatal, J. 1992. Handbook of the Birds of the World, vol. 1: Ostrich to Ducks. Lynx Edicions, Barcelona, Spain.
Delany, S.; Scott, D. 2006. Waterbird population estimates. Wetlands International, Wageningen, The Netherlands.
Evans, D. M.; Day, K. R. 2002. Hunting disturbance on a large shallow lake: the effectiveness of waterfowl refuges. Ibis 144(1): 2-8.
Fox, A. D.; Jones, T. A.; Singleton, R.; Agnew, A. D. Q. 1994. Food supply and the effects of recreational disturbance on the abundance and distribution of wintering Pochard on a gravel pit complex in southern Britain. Hydrobiologia 279/280: 253-262.
Giles, N. 1994. Tufted Duck (Aythya fuligula) habitat use and brood survival increases after fish removal from gravel pit lakes. Hydrobiologia 279/280: 387-392.
Gudmundsson, F. 1979. The past status and exploitation of the Myvatn waterfowl populations. Oikos 32((1-2)): 232-249.
Johnsgard, P. A. 1978. Ducks, geese and swans of the World. University of Nebraska Press, Lincoln and London.
Kear, J. 2005. Ducks, geese and swans volume 2: species accounts (Cairina to Mergus). Oxford University Press, Oxford, U.K.
Madge, S.; Burn, H. 1988. Wildfowl. Christopher Helm, London.
Marsden, S. J. 2000. Impact of Disturbance on Waterfowl Wintering in a UK Dockland Redevelopment Area. Environmental Management 26(2): 207-213.
Marsden, S. J.; Bellamy, G. S. 2000. Microhabitat characteristics of feeding sites used by diving duck Aythya wintering on the grossly polluted Manchester Ship Canal, UK. Environmental Conservation 27(3): 278-283.
Mateo, R.; Belliure, J.; Dolz, J. C.; Aguilar-Serrano, J. M.; Guitart, R. . 1998. High prevalences of lead poisoning in wintering waterfowl in Spain. Archives of Environmental Contamination and Toxicology 35: 342-347.
Melville, D. S.; Shortridge, K. F. 2006. Migratory waterbirds and avian influenza in the East Asian-Australasian Flyway with particular reference to the 2003-2004 H5N1 outbreak. In: Boere, G.; Galbraith, C., Stroud, D. (ed.), Waterbirds around the world, pp. 432-438. The Stationary Office, Edinburgh, UK.
Quan, R. C.; Wen, W.; Yang, X. 2002. Effects of human activities on migratory waterbirds at Lashihai Lake, China. Biological Conservation 108: 273-279.
Scott, D. A.; Rose, P. M. 1996. Atlas of Anatidae populations in Africa and western Eurasia. Wetlands International, Wageningen, Netherlands.
Snow, D. W.; Perrins, C. M. 1998. The Birds of the Western Palearctic vol. 1: Non-Passerines. Oxford University Press, Oxford.
Sorrenti, M.; Carnacina, L.; Radice, D.; Costato, A. 2006. Duck harvest in the Po delta, Italy. In: Boere, G.; Galbraith, C., Stroud, D. (ed.), Waterbirds around the world, pp. 864-865. The Stationary Office, Edinburgh, UK.
Further web sources of information
Detailed regional assessment and species account from the European Red List of Birds (BirdLife International, 2015)
Detailed species account from Birds in Europe: population estimates, trends and conservation status (BirdLife International 2004)
Explore HBW Alive for further information on this species
Search for photos and videos, and hear sounds of this species from the Internet Bird Collection
Text account compilers
Ekstrom, J., Butchart, S., Malpas, L.
IUCN Red List evaluators
Butchart, S., Symes, A.
BirdLife International (2015) Species factsheet: Aythya ferina. Downloaded from
http://www.birdlife.org on 01/09/2015.
Recommended citation for factsheets for more than one species: BirdLife International (2015) IUCN Red List for birds. Downloaded from
http://www.birdlife.org on 01/09/2015.
This information is based upon, and updates, the information published in BirdLife International (2000)
Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004)
Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.
To provide new information to update this factsheet or to correct any errors, please email BirdLife
To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.
Additional resources for this species