Justification 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). The population trend is not known, but the population is not believed to be decreasing sufficiently rapidly to approach the thresholds 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.

Family/Sub-family Anatidae

Species name author Linnaeus, 1758

Taxonomic source(s) AERC TAC (2003), AOU checklist (1998 + supplements), Cramp and Simmons (1977-1994), Dowsett and Forbes-Watson (1993), Sibley and Monroe (1990, 1993), Stotz et al. (1996)

Population estimate

Population trend

Range estimate (breeding/resident)

Country endemic?

3,200,000 - 3,800,000

unset

18,200,000 km²

No

Important Bird Areas Click here to view map showing IBAs where species is recorded and triggers any of the IBA criteria.

Ecology: Behaviour The species is strongly migratory in the north of its range² although breeding populations in temperate regions are largely sedentary¹. Males leave the breeding grounds in early-July (one month before the females and young), migrating to key waters to undergo a flightless moulting period lasting for c.4 weeks, after which they continue to the wintering grounds⁵. The return migration occurs from March to April⁵, and although the timing of the breeding season varies geographically the species generally nests late in the year (e.g. May-July)². It breeds in single pairs or loose groups¹ and is usually observed in small parties outside of the breeding season, with large concentrations sometimes forming on passage³ or during the moulting period^{2, 3}. Habitat The species inhabits highly productive^{1, 2} and eutrophic⁶ freshwater marsh or lake habitats^{1, 2} in open lowland grassland^{3, 4}, showing a preference for sheltered, shallow, standing or slow-flowing waters⁶ with abundant emergent vegetation^{1, 2, 4, 6} and grass-covered islands providing cover for nesting^{1, 4, 6}. It may also be found on permanent, shallow, slightly alkaline marshes^{1, 4}, as well as on oxbow lakes, channels⁸, reservoirs and gravel-pits². After hatching, females move their broods to deeper marshes or to the edges of large impoundments, sometimes more than 1 mile away from the nesting sites⁴. Rarely (e.g. in the winter)³ the species occurs along sheltered coasts^{1, 5} at coastal marshes (North America)², estuaries^{3, 6, 8}, deltas or lagoons⁶. Diet The species is predominantly herbivorous¹, its diet consisting of the seeds, leaves, roots and stems of aquatic plants¹ (submerged and emergent) as well as grasses and stoneworts Chara spp.², occasionally also taking cereal grains on land^{6, 7}. In addition, the species may take a small amount of animal matter during the winter (Africa), such as insects, molluscs, annelids, amphibians, amphibian spawn and small fish⁷. Breeding site The nest is a well-hidden⁴ hollow⁶ in grass and leaves positioned on the ground in thick vegetation¹ such as nettles Urtica spp.³, grass tussocks, thick bushes, rushes or tall grass⁷. The species shows a preference for dense, dry herbaceous vegetation⁴ and often nests far from water^{2, 3}. It may nest in dense concentrations on islands^{2, 3} (neighbouring nests as close as 5 m apart)⁶ although it is not a colonial species^{2, 3}. Management information The cyclical removal of adult fish from an artificial waterbody (gravel pit) in the UK (leaving small fish for piscivorous birds) resulted in an increase in the winter use of the habitat by the species as result of an increase in the growth of submerged aquatic macrophytes¹⁷. The removed fish (dead or alive) were sold to generate funds¹⁷.

Threats The species is threatened by pollution² and disturbance from recreational use of freshwater wetlands^{2, 13}. It also suffers mortality as a result of lead shot ingestion (Spain)¹⁵ and nest predation by American mink Neovison vison (Europe)¹⁶. The species is susceptible to avian influenza, so may be threatened by future outbreaks⁹. Utilisation The species is hunted throughout most of its range² both for recreation^{10, 11} and commercial uses¹², but is rarely taken in large numbers except where it is particularly abundant². The eggs of this species used to be (and possibly still are) harvested in Iceland¹⁴.

References 1. del Hoyo et al. (1992). 2. Kear (2005b). 3. Madge and Burn (1988). 4. Johnsgard (1978). 5. Scott and Rose (1996). 6. Snow and Perrins (1998). 7. Brown et al. (1982). 8. Flint et al. (1984). 9. Melville and Shortridge (2006). 10. Bregnballe et al. (2006). 11. Shortridge et al. (2006). 12. Balmaki and Barati (2006). 13. Pease et al. (2005). 14. Gudmundsson (1979). 15. Mondain-Monval et al. (2002). 16. Opermanis et al. (2001). 17. Giles (1994).

Further web sources of information

Detailed species account from Birds in Europe: population estimates, trends and conservation status (BirdLife International 2004)

Text account compilers Stuart Butchart (BirdLife International), Jonathan Ekstrom (BirdLife International), Lucy Malpas (BirdLife International)

IUCN Red List evaluators Jeremy Bird (BirdLife International), Stuart Butchart (BirdLife International)

Recommended citation BirdLife International (2009) Species factsheet: Anas strepera. Downloaded from http://www.birdlife.org on 10/2/2010

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.

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