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Common Merganser Mergus merganser

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 Medium
Land mass type   Average mass -


  Estimate Data quality
Extent of Occurrence breeding/resident (km2) 9,750,000 medium
Extent of Occurrence non-breeding (km2) 9,750,000 medium
Number of locations -
Fragmentation -

Population & trend

  Estimate Data quality Derivation Year of estimate
No. of mature individuals poor Estimated 2009
Population trend Increasing -
Number of subpopulations - - -
Largest subpopulation - - -
Generation length (yrs) 7.3 - - -
Population justification: The global population is estimated to number c.1,700,000-2,400,000 individuals (Wetlands International 2006), while national population estimates include: c.100-10,000 breeding pairs and c.50-1,000 wintering individuals in China; <c.100 breeding pairs and c.1,000-10,000 wintering individuals in Korea and c.1,000 wintering individuals in Japan (Brazil 2009).
Trend justification: The overall population trend is increasing, although some populations may be stable and others have unknown trends (Wetlands International 2006). This species has undergone a small or statistically insignificant increase over the last 40 years in North America (data from Breeding Bird Survey and/or Christmas Bird Count: Butcher and Niven 2007).

Country/Territory distribution

Country/Territory Occurrence status Presence Breeding Non-breeding Passage
Afghanistan Native Extant Yes    
Albania Native Extant      
Algeria Vagrant Extant      
Austria Native Extant      
Azerbaijan Native Extant   Yes  
Bangladesh Native Extant      
Belarus Native Extant     Yes
Belgium Native Extant   Yes  
Bermuda (to UK) Native Extant      
Bhutan Native Extant      
Bosnia and Herzegovina Native Extinct Yes    
Bulgaria Native Extant   Yes  
Canada Native Extant     Yes
China (mainland) Native Extant      
Croatia Native Extant      
Cyprus Vagrant Extant      
Czech Republic Native Extant      
Denmark Native Extant      
Estonia Native Extant     Yes
Finland Native Extant     Yes
France Native Extant     Yes
Germany Native Extant     Yes
Greece Native Extant      
Greenland (to Denmark) 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      
Israel Vagrant Extant      
Italy Native Extant      
Japan Native Extant      
Kazakhstan Native Extant Yes    
Kyrgyzstan Native Extant      
Latvia Native Extant     Yes
Lebanon Native Extant      
Liechtenstein Native Extant   Yes  
Lithuania Native Extant     Yes
Luxembourg Native Extant   Yes  
Macedonia, the former Yugoslav Republic of Native Extant      
Malta Vagrant Extant      
Mexico Native Extant      
Moldova Native Extant      
Mongolia Native Extant Yes    
Montenegro Native Extant      
Morocco Vagrant Extant      
Myanmar Native Extant      
Nepal Native Extant      
Netherlands Native Extant   Yes  
North Korea Native Extant      
Norway Native Extant     Yes
Pakistan Native Extant      
Poland Native Extant     Yes
Portugal Vagrant Extant      
Romania Native Extant     Yes
Russia (Asian) Native Extant Yes    
Russia (Central Asian) Native Extant Yes    
Russia (European) Native Extant     Yes
Serbia Native Extant      
Slovakia Native Extant   Yes  
Slovenia Native Extant      
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
Switzerland Native Extant      
Taiwan (China) Native Extant      
Tajikistan Native Extant Yes    
Tunisia Vagrant Extant      
Turkey Native Extant   Yes  
Turkmenistan Native Extant      
Ukraine Native Extant     Yes
United Kingdom Native Extant      
USA Native Extant Yes    
Uzbekistan Native Extant Yes    

Important Bird Areas where this species has triggered the IBA criteria

Country/Territory IBA Name IBA link
Bosnia and Herzegovina Livno karst field and Busko lake site factsheet
Canada Niagara River Corridor site factsheet
China (mainland) Burqin River and Kanas Lake site factsheet
China (mainland) Heyang Huang He Wetlands Nature Reserve site factsheet
China (mainland) Hongjian Nur site factsheet
China (mainland) Sayram Nur site factsheet
Croatia Donji Miholjac fish-ponds site factsheet
Denmark Arresø site factsheet
Denmark Hovvig site factsheet
Denmark Lovns Bredning site factsheet
Denmark Norsminde (Kysing) Fjord site factsheet
Denmark Roskilde Fjord, Selsø and Kattinge Søerne site factsheet
Denmark Smålandsfarvandet site factsheet
Estonia Lahemaa site factsheet
Estonia Väinameri site factsheet
Finland Kangasala wetlands site factsheet
Finland Kokkola and Kälviä archipelago site factsheet
Finland Köyliönjärvi and Pyhäjärvi lakes site factsheet
Finland Krunnit archipelago site factsheet
Finland Laajalahti bay, Vanhankaupunginlahti bay and Viikki site factsheet
Finland Merenkurkku archipelago site factsheet
Finland Mietoistenlahti bay site factsheet
Finland Oulu region wetlands site factsheet
Finland Paimionlahti bay site factsheet
Finland Pori archipelago and wetlands site factsheet
Finland Porvoonjoki Delta site factsheet
Finland Tornionjoki Delta site factsheet
Greece Lake Kastoria (Orestiada) site factsheet
Iceland Apavatn-Laugarvatn site factsheet
Iceland Mývatn-Laxá site factsheet
Iceland Sog site factsheet
India The Chapories of Lohit Reserve site factsheet
Kazakhstan Korgalzhyn State Nature Reserve site factsheet
Latvia Nida-Perkone site factsheet
Latvia Seaway to the border with Lithuania site factsheet
Lithuania Marine waters along the continental part of Lithuania site factsheet
Lithuania Marine waters along the Curonian Spit site factsheet
Lithuania Nemunas delta regional Park site factsheet
Lithuania The northern part of the Curonian Lagoon site factsheet
Mongolia Khar Lake site factsheet
Mongolia Khar Us Lake site factsheet
Mongolia Khovsgol Lake site factsheet
Mongolia Terkhiin Tsagaan Lake site factsheet
Netherlands Lake IJsselmeer site factsheet
Netherlands Steile Bank and Mokkebank site factsheet
Norway Inner part of Porsanger fjord site factsheet
Norway Tanamunningen site factsheet
Poland Delta of the Swina river site factsheet
Poland Lower Odra river valley site factsheet
Poland Puck Bay site factsheet
Poland Slowinski National Park site factsheet
Poland Szczecin lagoon site factsheet
Poland Vistula river mouth site factsheet
Romania Black Sea site factsheet
Romania Buhuşu reservoir - Bacău - Tătărăşti site factsheet
Romania Danube Delta site factsheet
Romania Olt valley site factsheet
Russia (Asian) Babushkina bay site factsheet
Russia (Asian) Bolon' lake site factsheet
Russia (Asian) Karaginskiy island site factsheet
Russia (Asian) Kuril'skoye lake site factsheet
Russia (Central Asian) Basins of the Schuchya and Khadytayakha rivers site factsheet
Russia (Central Asian) Kondinskiye lakes site factsheet
Russia (European) Berezovye islands of Vyborg Bay site factsheet
Russia (European) Kuloy river site factsheet
Russia (European) Kurgalski Peninsula site factsheet
Russia (European) Vaygach island site factsheet
Slovenia River Drava site factsheet
Slovenia Srednja Sava site factsheet
South Korea Han-gang river site factsheet
Sweden Lake Åsnen site factsheet
Sweden Lake Skedviken site factsheet
Sweden Outer Stockholm archipelago site factsheet
Sweden River Umeälven delta site factsheet
Sweden Western part of lake Mälaren site factsheet
Switzerland Lake Geneva: Rolle to Céligny site factsheet
Switzerland Lake Geneva: Versoix and Hermance to Geneva site factsheet
Switzerland Lake Neuchâtel: southern shore site factsheet
Switzerland River Rhone: Geneva to Verbois reservoir site factsheet
Tajikistan Bulunkul and Yashilkul lakes and mountains site factsheet
Tajikistan Dashtidjum site factsheet
Tajikistan Drumkul Lake site factsheet
Tajikistan Dzhavshangoz site factsheet
Tajikistan Karakul lake and mountains site factsheet
Ukraine Burshtyns'ke reservoir site factsheet
Ukraine Kanivs'kyi Nature Reserve site factsheet
USA Niagara River Corridor site factsheet
Uzbekistan Tudakul and Kuymazar Reservoirs site factsheet

Habitats & altitude

Habitat (level 1) Habitat (level 2) Importance Occurrence
Forest Boreal suitable breeding
Forest Temperate suitable breeding
Marine Neritic Estuaries suitable non-breeding
Marine Neritic Macroalgal/Kelp suitable non-breeding
Marine Neritic Seagrass (Submerged) suitable non-breeding
Marine Neritic Subtidal Loose Rock/pebble/gravel suitable non-breeding
Marine Neritic Subtidal Rock and Rocky Reefs suitable non-breeding
Marine Neritic Subtidal Sandy suitable non-breeding
Marine Neritic Subtidal Sandy-Mud suitable non-breeding
Wetlands (inland) Permanent Freshwater Lakes (over 8ha) major breeding
Wetlands (inland) Permanent Freshwater Lakes (over 8ha) major non-breeding
Wetlands (inland) Permanent Rivers/Streams/Creeks (includes waterfalls) major breeding
Wetlands (inland) Permanent Saline, Brackish or Alkaline Lakes suitable non-breeding
Altitude 1900 - 1900 m Occasional altitudinal limits  


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: Mergus merganser. Downloaded from on 18/04/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from on 18/04/2014.

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, 1758
Population size mature individuals
Population trend Increasing
Distribution size (breeding/resident) 9,750,000 km2
Country endemic? No
Links to further information
- Summary information on this species