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Greater Scaup Aythya marila

IUCN Red List history

Year Category
2012 Least Concern
2009 Least Concern
2008 Least Concern
2004 Least Concern
2000 Lower Risk/Least Concern
1994 Lower Risk/Least Concern
1988 Lower Risk/Least Concern

Species attributes

Migratory status full migrant Forest dependency Does not normally occur in forest
Land mass type   Average mass -


  Estimate Data quality
Extent of Occurrence breeding/resident (km2) 4,030,000 medium
Extent of Occurrence non-breeding (km2) 4,030,000 medium
Number of locations -
Fragmentation -

Population & trend

  Estimate Data quality Derivation Year of estimate
No. of mature individuals poor Estimated 2009
Population trend Decreasing -
Number of subpopulations - - -
Largest subpopulation - - -
Generation length (yrs) 8.2 - - -
Population justification: The global population is estimated to number c.1,200,000-1,400,000 individuals (Wetlands International 2006), while national population sizes have been estimated at c.50-1,000 individuals on migration and c.50-1,000 wintering individuals in Taiwan and c.1,000 wintering individuals in Korea (Brazil 2009).
Trend justification: The overall population trend is decreasing, although some populations may be stable or increasing and others have unknown trends (Wetlands International 2006). This species has underwent a significant population increase between 1974 and 2011 in North America (Zimpfer 2011, T. McCoy in litt. 2012).

Country/Territory distribution

Country/Territory Occurrence status Presence Breeding Non-breeding Passage
Afghanistan Vagrant Extant      
Albania Native Extant   Yes  
Algeria Vagrant Extant      
Antigua and Barbuda Native Extant     Yes
Austria Native Extant   Yes  
Azerbaijan Native Extant   Yes  
Bahamas Native Extant      
Bangladesh Native Extant      
Barbados Vagrant Extant      
Belarus Native Extant     Yes
Belgium Native Extant   Yes  
Bermuda (to UK) Native Extant      
Bonaire, Sint Eustatius and Saba (to Netherlands) Native Extant     Yes
Bosnia and Herzegovina Native Extant      
Bulgaria Native Extant   Yes Yes
Canada Native Extant     Yes
China (mainland) Native Extant      
Costa Rica Native Extant   Yes  
Croatia Native Extant   Yes  
Cuba Native Extant      
Curaçao (to Netherlands) Native Extant     Yes
Cyprus Vagrant Extant      
Denmark Native Extant   Yes Yes
Egypt Unknown Extant      
Estonia Native Extant     Yes
Faroe Islands (to Denmark) Native Extant   Yes  
Finland Native Extant     Yes
France Native Extant   Yes Yes
Georgia Unknown Extant      
Germany Native Extant     Yes
Gibraltar (to UK) Vagrant Extant      
Greece Native Extant   Yes  
Greenland (to Denmark) Vagrant Extant      
Guam (to USA) Unknown Extant      
Hong Kong (China) Vagrant Extant      
Hungary Native Extant   Yes  
Iceland Native Extant      
India Native Extant      
Iran, Islamic Republic of Native Extant   Yes  
Iraq Native Extant   Yes  
Ireland Native Extant   Yes  
Israel Vagrant Extant      
Italy Native Extant   Yes  
Jamaica Vagrant Extant      
Japan Native Extant      
Kazakhstan Native Extant      
Latvia Native Extant     Yes
Liechtenstein Native Extant      
Lithuania Native Extant   Yes  
Luxembourg Native Extant      
Macedonia, the former Yugoslav Republic of Native Extant   Yes  
Malta Vagrant Extant      
Mexico Native Extant      
Mongolia Vagrant Extant      
Montenegro Native Extant   Yes  
Morocco Vagrant Extant      
Myanmar Native Extant      
Nepal Native Extant      
Netherlands Native Extant   Yes  
North Korea Native Extant      
Northern Mariana Islands (to USA) Native Extant   Yes  
Norway Native Extant      
Pakistan Native Extant      
Philippines Native Extant      
Poland Native Extant   Yes Yes
Portugal Native Extant   Yes  
Puerto Rico (to USA) Native Extant      
Romania Native Extant   Yes Yes
Russia (Asian) Native Extant Yes    
Russia (Central Asian) Native Extant Yes   Yes
Russia (European) Native Extant Yes   Yes
Serbia Native Extant   Yes  
Sint Maarten (to Netherlands) Native Extant     Yes
Slovakia Native Extant   Yes  
Slovenia Native Extant   Yes  
South Korea Native Extant      
Spain Native Extant   Yes  
St Pierre and Miquelon (to France) Native Extant     Yes
Svalbard and Jan Mayen Islands (to Norway) Vagrant Extant      
Sweden Native Extant     Yes
Switzerland Native Extant   Yes  
Taiwan (China) Native Extant      
Tunisia Vagrant Extant      
Turkey Native Extant   Yes  
Turkmenistan Native Extant      
Turks and Caicos Islands (to UK) Native Extant      
Ukraine Native Extant     Yes
United Kingdom Native Extant      
USA Native Extant Yes    
Vietnam Native Extant      
Virgin Islands (to USA) Vagrant Extant      

Important Bird Areas where this species has triggered the IBA criteria

Country/Territory IBA Name IBA link
Canada Greater Rondeau Area site factsheet
Canada Niagara River Corridor site factsheet
Canada Old Crow Flats site factsheet
Canada Presqu'ile Provincial Park site factsheet
Canada Prince Edward Point site factsheet
Canada West End of Lake Ontario site factsheet
Canada Wolfe Island site factsheet
Denmark Horsens Fjord, Svanegrunden & Endelave site factsheet
Denmark Northwestern Kattegat site factsheet
Denmark Odense Fjord site factsheet
Estonia Irbe strait site factsheet
Estonia Nõva-Osmussaar site factsheet
Estonia Pakri site factsheet
Estonia Pärnu bay (NEW) site factsheet
Estonia Väinameri site factsheet
Estonia Vilsandi archipelago site factsheet
Finland Käsivarsi fjelds site factsheet
Finland Kevo site factsheet
Finland Sammutinjänkä-Vaijoenjänkä site factsheet
France Baie de Vilaine site factsheet
France Boucle de Pose et de Muids site factsheet
France Estuaire et embouchure de la Seine site factsheet
France Lac Léman (partie française) site factsheet
France Littoral Augeron site factsheet
France Traicts et marais salants de la Presqu'île Guérandaise site factsheet
Iceland Miklavatn-Skógar site factsheet
Iceland Mývatn-Laxá site factsheet
Japan Banzu and Futtsu tidal flat site factsheet
Japan Inner Tokyo bay site factsheet
Japan Isahaya bay site factsheet
Japan Lake Furenko and nearby wetlands site factsheet
Japan Lake Hamanako site factsheet
Japan Lake Nakaumi site factsheet
Japan Lake Shinjiko site factsheet
Japan Notsuke bay, Odaito site factsheet
Japan Shiokawa tidal flat site factsheet
Japan Yahagigawa estuary site factsheet
Latvia Irbe strait site factsheet
Netherlands Lake IJsselmeer site factsheet
Netherlands Lake Markermeer site factsheet
Netherlands Makkumer-and Kooiwaard site factsheet
Netherlands Steile Bank and Mokkebank site factsheet
Netherlands Voordelta site factsheet
Netherlands Wadden Sea site factsheet
Poland Lower Odra river valley site factsheet
Poland Puck Bay site factsheet
Poland Szczecin lagoon site factsheet
Romania Black Sea site factsheet
Russia (Asian) Abyy lowland site factsheet
Russia (Asian) Bolon' lake site factsheet
Russia (Asian) Kamchatka river mouth area site factsheet
Russia (Asian) Kharchinskoye lake site factsheet
Russia (Asian) Kolyma-Alazeya lowland site factsheet
Russia (Asian) Korfa bay (northern part) site factsheet
Russia (Asian) Lebediny refuge (Markovo depression) site factsheet
Russia (Asian) Lower Anadyr lowlands site factsheet
Russia (Asian) North-east Sakhalin lagoons site factsheet
Russia (Asian) Ola lagoon site factsheet
Russia (Asian) Parapol'skiy valley site factsheet
Russia (Central Asian) Basins of the Schuchya and Khadytayakha rivers site factsheet
Russia (Central Asian) Dvuob'ye site factsheet
Russia (Central Asian) Kondinskiye lakes site factsheet
Russia (Central Asian) Lower Ob' site factsheet
Russia (Central Asian) Lower Yuribey site factsheet
Russia (Central Asian) Upper and Middle Yuribey site factsheet
Russia (European) Berezovye islands of Vyborg Bay site factsheet
Russia (European) Bulgarski site factsheet
Russia (European) Floodplains of the Unzha river near Kologriv site factsheet
Russia (European) Kamsko-Ikski area site factsheet
Russia (European) Lapland Biosphere Reserve site factsheet
Russia (European) Lower Eruslan site factsheet
Russia (European) Manturovo left bank of the Unzha river site factsheet
Russia (European) Middle reaches of Bolshaya Rogovaya river site factsheet
Russia (European) North-western subburbs of St.-Petersburg site factsheet
Russia (European) Petrocrepost' Bay site factsheet
Russia (European) Russki Zavorot Peninsula and eastern part of Malozemelskaya Tundra site factsheet
Russia (European) Torna - Shoina watershed site factsheet
Russia (European) Unskaya bay site factsheet
Sweden Coastal areas of eastern Gotland island site factsheet
Sweden Strandstuguviken site factsheet
Ukraine Molochnyj Liman site factsheet
Ukraine Obytichna peninsula site factsheet
Ukraine Utlyuk lyman site factsheet
Ukraine Yagorlyts'ka and Tendrivs'ka Bays site factsheet
United Kingdom Bridgend Flats, Islay site factsheet
United Kingdom Carlingford Lough site factsheet
United Kingdom Loch Ryan site factsheet
United Kingdom Lochs of Harray and Stenness site factsheet
United Kingdom Lough Neagh and Lough Beg site factsheet
United Kingdom Moray Basin, Firths and Bays site factsheet
United Kingdom Moray Basin, Firths and Bays site factsheet
United Kingdom Upper Solway Flats and Marshes site factsheet

Habitats & altitude

Habitat (level 1) Habitat (level 2) Importance Occurrence
Grassland Tundra suitable breeding
Marine Neritic Estuaries major non-breeding
Marine Neritic Macroalgal/Kelp major non-breeding
Marine Neritic Pelagic marginal non-breeding
Marine Neritic Seagrass (Submerged) major non-breeding
Marine Neritic Subtidal Loose Rock/pebble/gravel major non-breeding
Marine Neritic Subtidal Rock and Rocky Reefs major non-breeding
Marine Neritic Subtidal Sandy major non-breeding
Marine Neritic Subtidal Sandy-Mud major non-breeding
Wetlands (inland) Bogs, Marshes, Swamps, Fens, Peatlands suitable breeding
Wetlands (inland) Permanent Freshwater Lakes (over 8ha) suitable breeding
Wetlands (inland) Permanent Freshwater Lakes (over 8ha) suitable non-breeding
Wetlands (inland) Permanent Rivers/Streams/Creeks (includes waterfalls) suitable breeding
Altitude 0 - 0 m Occasional altitudinal limits  

Threats & impact

Threat (level 1) Threat (level 2) Impact and Stresses
Climate change & severe weather Habitat shifting & alteration Timing Scope Severity Impact
Future Whole (>90%) Unknown Unknown
Indirect ecosystem effects, Ecosystem degradation


Purpose Primary form used Life stage used Source Scale Level Timing
Food (human) Whole Adults and juveniles Wild Subsistence, National Non-trivial Recent
Pets Whole Adults and juveniles Wild International Non-trivial Recent
Sport Whole Adults and juveniles Wild Subsistence, National Non-trivial Recent

Recommended citation
BirdLife International (2014) Species factsheet: Aythya marila. Downloaded from on 11/07/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from on 11/07/2014.

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.

Key facts
Current IUCN Red List category Least Concern
Family Anatidae (Ducks, geese and swans)
Species name author (Linnaeus, 1761)
Population size mature individuals
Population trend Decreasing
Distribution size (breeding/resident) 4,030,000 km2
Country endemic? No
Links to further information
- Summary information on this species