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). 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.

Family/Sub-family Anatidae

Species name author Linnaeus, 1758

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

Taxonomic note Anas platyrhynchos (Sibley and Monroe 1990, 1993) was provisionally split into A. platyrhynchos and A. diazi by Stotz et al. (1996) but this treatment has not been adopted, following SACC (2005).

Population estimate

Population trend

Range estimate (breeding/resident)

Country endemic?

19,000,000

unset

36,100,000 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 In temperate regions breeding populations of this species are sedentary or dispersive, often making local movements during severe weather⁵. Other populations are fully migratory² with females and juveniles leaving the breeding grounds in the western Palearctic from September and returning as early as February⁵. The species breeds between March and June³ in single pairs or loose groups¹ although the exact timing varies with latitude³. While the females are incubating⁴ (from mid-May)^{5, 6} the males gather³ in small flocks and migrate to moulting areas⁶ where they undergo a flightless moulting period lasting for c.4 weeks⁵ (females moult near the breeding grounds)⁶. Outside of the breeding season the species can be found in small to very large flocks³ numbering up to several hundreds or even thousands of individuals⁷ especially when moulting⁵, on migration⁷ and during the winter². The species may also roost both nocturnally and diurnally in communal groups when not breeding⁸. Habitat The species occurs in almost every wetland type¹ although it generally avoids fast-flowing, oligotrophic^{1, 5, 7}, deep, exposed, rough, rockbound waters and hard unvegetated areas such as rocky ground, sand dunes and artificial surfacing⁷. It requires water less than 1 m deep for foraging⁷ and shows a preference for freshwater habitats³ although it may frequent shallow brackish waters as long as they provide the cover^{1, 5} of submerged, floating, emergent or riparian vegetation, dense reedbeds or overhanging branches⁷. Habitats commonly frequented include flooded swampy woodlands, seasonal floodlands⁷, wet grassy swamps and meadows, oxbow lakes⁶, open waters with mudflats, banks or spits, irrigation networks, reservoirs, ornamental waters^{1, 5, 7}, canals and sewage farms⁷. During the winter the species may also be found in saline habitats along the coast³ where water is shallow, fairly sheltered and within site of land⁷ (e.g. brackish lagoons⁷, brackish estuaries^{1, 7} and bays¹). Diet The species is omnivorous and opportunistic^{1, 7}, feeding by dabbling in water and by grazing on the land⁷. Its diet consists of seeds and the vegetative parts of aquatic and terrestrial plants (e.g. crops)¹, as well as terrestrial and aquatic invertebrates (especially in the spring and summer) such as insects, molluscs, crustaceans, worms and occasionally amphibians and fish¹. Breeding site The nest is a shallow depression⁷ or bowl of vegetation that can be situated in many different locations such as within vegetation on the ground, in natural tree cavities¹ up to 10 m high (Africa)⁸, under fallen dead wood, on tree stumps⁶, under bushes⁸ and even in abandoned nests of other species (e.g. herons or crows)⁶. Nests are generally placed close to water² although occasionally they may be some distance away³. Management information "Extensive" grazing of wetland grasslands (c.0.5 cows per hectare) was found to attract a higher abundance of the species in Hungary¹⁹. Studies in Danish coastal wetlands found that the spatial restriction of shore-based shooting was more successful at maintaining waterfowl population sizes than was the temporal restriction of shooting, and therefore that wildfowl reserves should incorporate shooting-free refuges that include adjacent marshland in order to ensure high waterfowl species diversity²⁰. The cyclical removal of adult fish from an artificial waterbody (gravel pit) in the UK resulted in an increase in invertebrate food availability and an increase in the growth of submerged aquatic macrophytes, which in turn led to an increased use of the habitat for brood rearing by the species²⁶. The removed fish (dead or alive) were sold to generate funds²⁶. The species will also nest in artificial nest boxes^{1, 8}.

Threats The species is threatened by wetland habitat degradation and loss from pollution (e.g. petroleum⁹ and pesticide pollution²²), wetland drainage, peat-extraction, changing wetland management practices (e.g. decreased grazing and mowing in meadows leading to scrub over-growth) and the burning and mowing of reedbeds⁹. The species also suffers mortality as a result of lead shot ingestion (e.g. in Spain²¹ and France²⁴) and poisoning from white phosphorous ingestion (from firearms) in Alaska¹⁸. It is also susceptible to duck virus enteritis (DVE)¹⁰, avian influenza¹² and avian botulism¹¹ so may be threatened by future outbreaks of these diseases (although it may be able to withstand sporadic losses due to its high reproductive potential)¹¹. The species is predated by American mink Neovison vison in Europe²⁵. Utilisation The species is hunted throughout the world² mainly for sport^{13, 14, 15, 17}, but also for commercial use (food)¹⁶. The eggs of this species were (and possibly still are) harvested in Iceland²³.

References 1. del Hoyo et al. (1992). 2. Kear (2005b). 3. Madge and Burn (1988). 4. Johnsgard (1978). 5. Scott and Rose (1996). 6. Flint et al. (1984). 7. Snow and Perrins (1998). 8. Brown et al. (1982). 9. Grishanov (2006). 10. Friend (2006). 11. Rocke (2006). 12. Melville and Shortridge (2006).13. Bregnballe et al. (2006). 14. Mondain-Monval et al. (2006). 15. Sorrenti et al. (2006). 16. Balmaki and Barati (2006). 17. Evans and Day (2002). 18. Steele (1997). 19. Baldi et al.(2005). 20. Bregnballe et al. (2004). 21. Mateo et al. (1999). 22. Kwon et al. (2004). 23. Gudmundsson (1979). 24. Mondain-Monval et al. (2002). 25. Opermanis et al. (2001). 26. 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 platyrhynchos. Downloaded from http://www.birdlife.org on 9/2/2010

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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