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Greater Scaup Aythya marila
BirdLife is updating this factsheet for the 2016 Red List
Please email us with any relevant information

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 Resident
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 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 Yes
Faroe Islands (to Denmark) Native Extant   Yes    
Finland Native Extant     Yes Yes
France Native Extant   Yes Yes  
Georgia Unknown Extant        
Germany Native Extant     Yes 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       Yes
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 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       Yes
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 Yes
Svalbard and Jan Mayen Islands (to Norway) Vagrant Extant        
Sweden Native Extant     Yes 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 Yes
United Kingdom Native Extant       Yes
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 Northern 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
Ireland Carlingford Lough site factsheet
Ireland Shannon and Fergus Estuaries site factsheet
Ireland Tacumshin lake site factsheet
Ireland Tralee Bay and Barrow Harbour site factsheet
Ireland Wexford Harbour and Slobs site factsheet
Japan Banzu and Futtsu tidal flat site factsheet
Japan Inner Tokyo bay site factsheet
Japan Isahaya bay site factsheet
Japan Lake Furen, On-netou site factsheet
Japan Lake Hamanako, Enshunada site factsheet
Japan Lake Nakaumi site factsheet
Japan Lake Shinjiko site factsheet
Japan Notsuke, Odaitou 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
Norway Dovrefjell site factsheet
Norway Hardangervidda site factsheet
Norway Reisa site factsheet
Norway Varanger Peninsula 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) Korf 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) Berezoviye 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 Bay of Torslandaviken site factsheet
Sweden Coastal areas of eastern Gotland island site factsheet
Sweden Lake Ånnsjön-Storlien site factsheet
Sweden Strandstuguviken site factsheet
Sweden Vindelfjällen mountains (including Lake Tärnasjön) 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 (2016) Species factsheet: Aythya marila. Downloaded from on 26/10/2016. Recommended citation for factsheets for more than one species: BirdLife International (2016) IUCN Red List for birds. Downloaded from on 26/10/2016.

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, 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
- 2015 European Red List assessment