Greater Scaup Aythya marila


Taxonomic source(s)
AERC TAC. 2003. AERC TAC Checklist of bird taxa occurring in Western Palearctic region, 15th Draft. Available at: # _the_WP15.xls#.
Cramp, S. and Simmons, K.E.L. (eds). 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. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 1: Non-passerines. Lynx Edicions BirdLife International, Barcelona, Spain and Cambridge, UK.

IUCN Red list criteria met and history
Red List criteria met
Critically Endangered Endangered Vulnerable
- - -

Red List history
Year Category Criteria
2018 Least Concern
2016 Least Concern
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 -
Extent of occurrence (EOO)

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 46,400,000 medium
Extent of Occurrence non-breeding (km2) 92,700,000 medium
Number of locations -
Fragmentation -
Population and trend
Estimate Data quality Derivation Year of estimate
No. of mature individuals 4900000-5199999 poor estimated 2015
Population trend Decreasing suspected -
Decline (3 years/1 generation past) - - -
Decline (5 years/1 generation past) - - -
Decline (10 years/1 generation past) - - -
Decline (10 years/3 generation future) - - -
Decline (10 years/3 generation past and future) - - -
Number of subpopulations - - -
Largest subpopulations - - -
Generation length (yrs) 8.2 - - -

Population justification: The global population is estimated to number c. 4,920,000-5,130,000 individuals (Wetlands International 2016). The breeding population in Europe is estimated at 134,000-178,000 pairs, which equates to 269,000-355,000 mature individuals (BirdLife International 2015).

Trend justification: The overall population trend is decreasing, although some populations may be stable or have unknown trends (Wetlands International 2016). This species underwent a significant population increase between 1974 and 2011 in North America (Zimpfer 2011, T. McCoy in litt. 2012). In Europe the breeding population size is estimated to be decreasing by less than 25% in 24.6 years (three grenerations) (BirdLife International 2015).

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

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Azerbaijan Aggyol
Azerbaijan Gizilagach State Reserve
Canada Greater Rondeau Area
Canada Niagara River Corridor
Canada Old Crow Flats
Canada Presqu'ile Provincial Park
Canada Prince Edward Point
Canada West End of Lake Ontario
Canada Wolfe Island
Denmark Horsens Fjord, Svanegrunden & Endelave
Denmark Northern Kattegat
Denmark Odense Fjord
Estonia Irbe strait
Estonia Nõva-Osmussaar
Estonia Pakri
Estonia Pärnu bay (NEW)
Estonia Väinameri
Estonia Vilsandi archipelago
Finland Käsivarsi fjelds
Finland Kevo
Finland Sammutinjänkä-Vaijoenjänkä
France Baie de Vilaine
France Boucle de Pose et de Muids
France Estuaire et embouchure de la Seine
France Lac Léman (partie française)
France Littoral Augeron
France Traicts et marais salants de la Presqu'île Guérandaise
Germany Brodtener Ufer
Germany Coast and lagoons of Western Pomerania
Germany Coastline of Probstei
Germany East- and south-east coast of Fehmarn
Germany Eastern bight of the Fehmarnsund
Germany Eastern part of Kiel Bight
Germany Flensburger Innen- and Aussenförde
Germany Greifswalder Bodden
Germany Grosser and Kleiner Binnensee
Germany Neustädter Bucht
Germany Sagasbank and eastern coast of Oldenburg
Germany Traveförde and Dassower See
Germany Wismar bay and Salzhaff
Iceland Miklavatn-Skógar
Iceland Mývatn-Laxá
Ireland Carlingford Lough
Ireland Lough Gill
Ireland Lough Swilly including Blanket Nook and Inch Lake
Ireland Tralee Bay and Barrow Harbour
Ireland Wexford Harbour and Slobs
Japan Banzu and Futtsu tidal flat
Japan Inner Tokyo bay
Japan Isahaya bay
Japan Lake Furen, On-netou
Japan Lake Hamanako, Enshunada
Japan Lake Nakaumi
Japan Lake Shinjiko
Japan Notsuke, Odaitou
Japan Shiokawa tidal flat
Japan Yahagigawa estuary
Latvia Irbe strait
Netherlands Delta Coast
Netherlands Lake IJsselmeer
Netherlands Makkumer-and Kooiwaard
Netherlands Markermeer & IJmeer
Netherlands Steile Bank and Mokkebank
Netherlands Wadden Sea
Norway Dovrefjell
Norway Hardangervidda
Norway Reisa
Norway Varanger Peninsula
Poland Lower Odra river valley
Poland Puck Bay
Poland Szczecin lagoon
Romania Black Sea
Russia (Asian) Abyy lowland
Russia (Asian) Bol'shaya River Estuary
Russia (Asian) Bolon' lake
Russia (Asian) Karaginskiy Island
Russia (Asian) Kharchinskoye lake
Russia (Asian) Kolyma-Alazeya lowland
Russia (Asian) Korfa Gulf (northern part)
Russia (Asian) Lebediny refuge (Markovo depression)
Russia (Asian) Lower Anadyr lowlands
Russia (Asian) Moroshechnaya River
Russia (Asian) Nerpich'ye Lake and Kamchatka River delta
Russia (Asian) North-east Sakhalin lagoons
Russia (Asian) Ola lagoon
Russia (Asian) Parapol'skiy valley
Russia (Central Asian) Basins of the Schuchya and Khadytayakha rivers
Russia (Central Asian) Dvuob'ye
Russia (Central Asian) Kondinskiye lakes
Russia (Central Asian) Lower Ob'
Russia (Central Asian) Lower Yuribey
Russia (Central Asian) Upper and Middle Yuribey
Russia (European) Berezoviye islands of Vyborg Bay
Russia (European) Bulgarski
Russia (European) Floodplains of the Unzha river near Kologriv
Russia (European) Kamsko-Ikski area
Russia (European) Lapland Biosphere Reserve
Russia (European) Lower Eruslan
Russia (European) Manturovo left bank of the Unzha river
Russia (European) Middle reaches of Bolshaya Rogovaya river
Russia (European) North-western subburbs of St.-Petersburg
Russia (European) Petrocrepost' Bay
Russia (European) Russki Zavorot Peninsula and eastern part of Malozemelskaya Tundra
Russia (European) Torna-Shoina watershed
Russia (European) Unskaya bay
Sweden Bay of Strandstugu
Sweden Bay of Torslanda
Sweden Coastal area of Eastern Gotland
Sweden Lake Ånn – Storlien
Sweden Vindel Mountains (including Lake Tärna)
Ukraine Molochnyj Liman
Ukraine Obytichna peninsula
Ukraine Utlyuk lyman
Ukraine Yagorlyts'ka and Tendrivs'ka Bays
United Kingdom Bridgend Flats, Islay
United Kingdom Carlingford Lough
United Kingdom Loch Ryan
United Kingdom Lochs of Harray and Stenness
United Kingdom Lough Neagh and Lough Beg
United Kingdom Moray Basin, Firths and Bays
United Kingdom Moray Basin, Firths and Bays
United Kingdom Upper Solway Flats and Marshes

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 non-breeding
Wetlands (inland) Permanent Freshwater Lakes (over 8ha) suitable breeding
Wetlands (inland) Permanent Rivers/Streams/Creeks (includes waterfalls) suitable breeding
Altitude   Occasional altitudinal limits  

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Biological resource use Fishing & harvesting aquatic resources - Unintentional effects: (large scale) [harvest] Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Indirect ecosystem effects, Ecosystem degradation, Species mortality
Biological resource use Hunting & trapping terrestrial animals - Intentional use (species is the target) Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Species mortality
Climate change & severe weather Habitat shifting & alteration Timing Scope Severity Impact
Ongoing Majority (50-90%) Negligible declines Low Impact: 5
Indirect ecosystem effects, Ecosystem degradation
Climate change & severe weather Other impacts Timing Scope Severity Impact
Ongoing Whole (>90%) Unknown Unknown
Indirect ecosystem effects
Energy production & mining Oil & gas drilling Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Species disturbance, Ecosystem degradation, Ecosystem conversion
Energy production & mining Renewable energy Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Species disturbance
Pollution Industrial & military effluents - Oil spills Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Indirect ecosystem effects, Ecosystem degradation, Species mortality

Purpose Primary form used Life stage used Source Scale Level Timing
Food - human - - Non-trivial Recent
Pets/display animals, horticulture - - International Non-trivial Recent
Sport hunting/specimen collecting - - Non-trivial Recent

Recommended citation
BirdLife International (2020) Species factsheet: Aythya marila. Downloaded from on 26/01/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from on 26/01/2020.