Red-breasted Merganser Mergus serrator


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 -

Estimate Data quality
Extent of Occurrence (breeding/resident) 64,500,000 km2 medium
Extent of Occurrence (non-breeding) 107,000,000 km2 medium
Severely fragmented? no -
Estimate Data quality Derivation Year of estimate
Population size unknown poor estimated 2016
Population trend stable - suspected -
Generation length 7.3 years - - -

Population justification: The global population is estimated to number c.495,000-605,000 individuals (Wetlands International 2016). The European population is estimated at 70,100-120,000 pairs, which equates to 140,000-240,000 mature individuals (BirdLife International 2015).

Trend justification: The overall population trend is stable, although some populations have unknown trends (Wetlands International 2016). This species has had stable population trends over the last 40 years in North America (data from Breeding Bird Survey and/or Christmas Bird Count: Butcher and Niven 2007). In Europe the population size is estimated to be decreasing at a rate approaching 30% in 21.9 years (three generations) (BirdLife International 2015).

Country/territory distribution
Country/Territory Presence Origin Resident Breeding visitor Non-breeding visitor Passage migrant
Afghanistan extant vagrant
Albania extant native yes
Algeria extant vagrant
Armenia extant native yes
Austria extant native yes
Azerbaijan extant native yes
Bahamas extant native
Bahrain extant vagrant yes
Belarus extant native yes yes
Belgium extant native yes
Belize extant vagrant
Bermuda (to UK) extant native
Bosnia and Herzegovina extant native
Bulgaria extant native yes
Canada extant native yes yes
Cayman Islands (to UK) extant vagrant
China (mainland) extant native
Croatia extant native yes
Cuba extant native
Cyprus extant native yes
Czechia extant native yes
Denmark extant native yes yes
Dominican Republic extant vagrant yes
Egypt extant native
Estonia extant native yes yes
Faroe Islands (to Denmark) extant native yes
Finland extant native yes yes
France extant native yes yes
Germany extant native yes yes
Gibraltar (to UK) extant vagrant
Greece extant native yes
Greenland (to Denmark) extant native yes
Haiti extant vagrant
Hungary extant native yes
Iceland extant native yes
India extant vagrant
Iran, Islamic Republic of extant native yes
Iraq extant native
Ireland extant native yes
Israel extant native
Italy extant native yes
Japan extant native
Jordan extant vagrant
Kazakhstan extant native yes
Kuwait extant vagrant yes
Kyrgyzstan extant native yes
Latvia extant native yes
Lebanon extant vagrant yes
Libya extant native
Liechtenstein extant native
Lithuania extant native yes yes
Luxembourg extant vagrant
Malta extant native
Mexico extant native
Moldova extant native yes
Mongolia extant vagrant
Montenegro extant native yes
Morocco extant native
Nepal extant vagrant
Netherlands extant native yes
North Korea extant native
North Macedonia extant native yes
Northern Mariana Islands (to USA) extant vagrant
Norway extant native yes yes
Oman extant vagrant yes
Pakistan extant native
Palestine extant vagrant yes
Philippines extant uncertain
Poland extant native yes yes
Portugal extant native yes
Puerto Rico (to USA) extant vagrant
Romania extant native yes yes
Russia extant native yes yes
Russia (Asian) extant native yes
Russia (Central Asian) extant native yes yes
Russia (European) extant native yes yes
Saudi Arabia extant vagrant yes
Serbia extant native yes
Slovakia extant native yes
Slovenia extant native yes
South Korea extant native
Spain extant native yes
St Pierre and Miquelon (to France) extant native yes
Svalbard and Jan Mayen Islands (to Norway) extant vagrant
Sweden extant native yes yes
Switzerland extant native yes
Syria extant vagrant yes
Taiwan, China extant native
Tunisia extant native
Türkiye extant native yes
Turkmenistan extant native
Turks and Caicos Islands (to UK) extant native
Ukraine extant native yes yes
United Arab Emirates extant vagrant yes
United Kingdom extant native yes
USA extant native yes
Uzbekistan extant native
Virgin Islands (to USA) extant vagrant

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Greenland (to Denmark) Ikkattoq fjord and islands
Sweden Archipelago of Stockholm
Sweden Fjord of Kungsbacka
Finland Merenkurkku archipelago
Finland Kokkola and Kälviä archipelago
Finland Rahja archipelago
Finland Oulu region wetlands
Russia (European) Berezoviye islands of Vyborg Bay
France Golfe du Morbihan et Etier de Penerf
Denmark Vestamager and adjacent sea area
Denmark Sydfynske Ø-hav
Denmark Eastern part of Vejlerne
Denmark Smålandsfarvandet
Denmark Hyllekrog-Rødsand and Fehmarn Belt
Denmark Ronne Banke
Iran, Islamic Republic of Miankaleh Peninsula and Gorgan Bay
Iran, Islamic Republic of Gomishan marshes and Turkoman steppes
Russia (Asian) Tyk and Viakhtu bays
Russia (Asian) Kuril islands (between Urup and Paramushir)
Russia (Asian) Lesser Kuril Ridge and Kunashir Island
Russia (Asian) Forty Islands
Russia (Asian) Nevskoye Lake
Russia (Asian) North-east Sakhalin lagoons
Russia (European) Kuloy river
Azerbaijan Gizilagach
Russia (Central Asian) Kuznetsky Alatau Zapovednik
Russia (Central Asian) Lower Ob'
Russia (Central Asian) Upper and Middle Yuribey
Russia (Central Asian) Basins of the Schuchya and Khadytayakha rivers
Canada Long Point Peninsula and Marshes
Canada Point Pelee
Sweden Falsterbo – Bay of Fote
Poland Pomeranian bay
Kazakhstan Tentek River Delta
Russia (Central Asian) Upper streams of Ob' river
Russia (Central Asian) Dvuob'ye
Germany Greifswalder Bodden
Germany Pomeranian bay
Germany Wismar bay and Salzhaff
Germany Coast and lagoons of Western Pomerania
USA Prince William Sound
Denmark Rønne Banke
Norway Neiden- & Munkefjord
Norway Tanamunningen
Norway Smøla archipelago
Norway Ørlandet
Norway Persfjorden - Hamningberg
Norway Været
Norway Inner Porsangerfjord
Norway Varangerfjord (including Hornøya and Reinøya)
Norway Solvær archipelago
Netherlands Grevelingen
Netherlands Haringvliet
Netherlands Lake IJsselmeer
Netherlands Oosterschelde
Netherlands Veerse Meer
Netherlands Wadden Sea
Netherlands Zoommeer
Russia (Asian) Karaginskiy Island
Russia (Asian) Nerpich'ye Lake and Kamchatka River delta
Russia (Asian) Bol'shaya River Estuary
Russia (Asian) Moroshechnaya River

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Marine Coastal/Supratidal Coastal Brackish/Saline Lagoons/Marine Lakes suitable non-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 Rivers/Streams/Creeks (includes waterfalls) major breeding
Altitude   Occasional altitudinal limits  

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Biological resource use Hunting & trapping terrestrial animals - Persecution/control Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Species disturbance, 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 (2024) Species factsheet: Mergus serrator. Downloaded from on 22/02/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from on 22/02/2024.