Mergus merganser -- Linnaeus, 1758ANIMALIA -- CHORDATA -- AVES -- ANSERIFORMES -- ANATIDAECommon names: Goosander;

European Red List AssessmentEuropean Red List Status

LC -- Least Concern, (IUCN version 3.1)

Assessment InformationYear published: 2015Date assessed: 2015-03-31Assessor(s): BirdLife InternationalReviewer(s): Symes, A.Compiler(s): Ashpole, J., Burfield, I., Ieronymidou, C., Pople, R., Wheatley, H. & Wright, L.Assessment RationaleEuropean regional assessment: Least Concern (LC)EU27 regional assessment: Least Concern (LC)

In Europe this species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence 10% in ten years or three generations, or with a specified population structure). The population trend appears to be stable, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (30% decline over ten years or three generations). For these reasons the species is evaluated as Least Concern in Europe.

Within the EU27 this species has a very large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence 10% in ten years or three generations, or with a specified population structure). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (30% decline over ten years or three generations). For these reasons the species is evaluated as Least Concern in the EU27.

OccurrenceCountries/Territories of OccurrenceNative:Albania; Austria; Azerbaijan; Belarus; Belgium; Bosnia and Herzegovina; Bulgaria; Croatia; Czech Republic; Denmark; Estonia; Finland; France; Germany; Greece; Hungary; Iceland; Ireland, Rep. of; Italy; Latvia; Liechtenstein; Lithuania; Luxembourg; Macedonia, the former Yugoslav Republic of; Moldova; Montenegro; Netherlands; Norway; Poland; Romania; Russian Federation; Serbia; Slovakia; Slovenia; Spain; Sweden; Switzerland; Turkey; Ukraine; United KingdomVagrant:Cyprus; Greenland (to DK); Malta; Svalbard and Jan Mayen (to NO); Portugal

PopulationThe European population is estimated at 66,800-103,000 pairs, which equates to 134,000-206,000 mature individuals. The population in the EU27 is estimated at 56,100-85,000 pairs, which equates to 112,000-170,000 mature individuals. For details of national estimates, see Supplementary PDF.

TrendIn Europe the population size is estimated to be stable. In the EU27 the population size is estimated to be decreasing by less than 25% in 21.9 years (three generations). For details of national estimates, see Supplementary PDF.

Habitats and EcologyThe species breeds on large clear freshwater lakes, pools, the upper reaches of rivers (Carboneras and Kirwan 2014) and streams in the boreal, montane (Kear 2005) and temperate forest zones (Johnsgard 1978). It requires waters with a fairly high productivity of fish surrounded by mature hardwood trees with holes

excavated by woodpeckers or natural cavities for nesting in (Kear 2005). The species winters on large unfrozen lakes, rivers, lagoons, brackish waters and marshes, generally avoiding highly saline waters (Madge and Burn 1988) although it may move to estuaries, coastal lagoons and sheltered sea coasts with waters less than 10 m deep in particularly harsh winters (Scott and Rose 1996). The species arrives on its breeding areas between March and May (Scott and Rose 1996), actually breeding as early as late-March (although often considerably later in more northerly regions) (Madge and Burn 1988).The species nests in holes excavated by large woodpeckers or natural cavities in mature hardwood trees with entry holes more than 15 m above the ground (Kear 2005). When natural tree-nesting sites are not available the species will use artificial nestboxes (Johnsgard 1978, Carboneras and Kirwan 2014) or may nest in rock clefts (Flint et al. 1984), among tree roots in undercut banks, on cliff ledges or in dense scrub or loose boulders on islands (Kear 2005). Clutches are usually eight to twelve eggs. Its diet consists predominantly of fish, but may also include aquatic invertebrates (such as molluscs, crustaceans, worms, and adult and larval insects), amphibians, small mammals and birds (Carboneras and Kirwan 2014). Northern breeding populations of this species are fully migratory (Snow and Perrins 1998) although breeders in temperate regions are sedentary or only travel short distances (Carboneras and Kirwan 2014).Habitats & Altitude

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

ThreatsThe species is subject to persecution by anglers and fish-farmers who accuse it of depleting fish stocks (Carboneras and Kirwan 2014). The species is also threatened by the degradation of freshwater lakes through drainage and petroleum pollution in Russia (Grishanov 2006). The species is susceptible to avian influenza so may be threatened by future outbreaks of the virus (Melville and Shortridge 2006). The species is hunted in Russia (Grishanov 2006) (although it is not a popular game bird (Kear 2005)), and its eggs used to be (and possibly still are) harvested in Iceland (Gudmundsson 1979).Threats & Impacts

Threat (level 1) Threat (level 2) Impact and StressesBiological resource use

Hunting & trapping terrestrial animals (intentional use - species is the target)

Timing Scope Severity ImpactOngoing Minority (<50%) Negligible declines Low Impact

StressesSpecies mortality

Biological resource use

Hunting & trapping terrestrial animals (persecution/control)

Timing Scope Severity ImpactOngoing Minority (<50%) Slow, Significant

DeclinesLow Impact

StressesSpecies mortality

Invasive and other problematic species, genes & diseases

Avian Influenza Virus (H subtype)

Timing Scope Severity ImpactPast, Likely to Return

Majority (50-90%) Rapid Declines Past Impact

StressesSpecies mortality

Threats & ImpactsThreat (level 1) Threat (level 2) Impact and Stresses

Natural system modifications

Abstraction of surface water

Timing Scope Severity ImpactOngoing Minority (<50%) Slow, Significant

DeclinesLow Impact

StressesEcosystem conversion; Ecosystem degradation

Pollution Oil spills Timing Scope Severity ImpactOngoing Minority (<50%) Causing/Could

cause fluctuationsLow Impact

StressesEcosystem conversion

ConservationConservation Actions UnderwayCMS Appendix II. EU Birds Directive Annex II. There are currently no known conservation measures for this species.

Conservation Actions ProposedThe erection of nest boxes may encourage the use of local areas by this species (Kear 2005). Future research to inform the conservation and management of this species should include investigations into its breeding requirements, winter habitats and population size (Mallory and Metz 1999). Strict legislation on petroleum drilling and transport should be enforced and important areas protected from drainage and other habitat modifications. Research into the impact this species has on fish stocks and ways to minimise conflict should be established.

BibliographyCarboneras, C. and Kirwan, G.M. 2014. Goosander (Mergus merganser). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. and de Juana, E. (eds.) 2014. Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/52931 on 3 March 2015).Flint, V.E., Boehme, R.L., Kostin, Y.V. and Kuznetsov, A.A. 1984. A field guide to birds of the USSR. Princeton University Press, Princeton, New Jersey.Grishanov, D. 2006. Conservation problems of migratory waterfowl and shorebirds and their habitats in the Kaliningrad region of Russia. In: Boere, G., Galbraith, C. and Stroud, D. (ed.), Waterbirds around the world, pp. 356. The Stationary Office, Edinburgh, UK.Gudmundsson, F. 1979. The past status and exploitation of the Myvatn waterfowl populations. Oikos 32(1-2): 232-249.Johnsgard, P.A. 1978. Ducks, geese and swans of the World. University of Nebraska Press, Lincoln and London.Kear, J. 2005. Ducks, geese and swans volume 2: species accounts (Cairina to Mergus). Oxford University Press, Oxford, U.K.Madge, S. and Burn, H. 1988. Wildfowl. Christopher Helm, London.Mallory, M. and Metz, K. 1999. Common merganser (Mergus merganser). In: Poole, A. (Ed.) The Birds of North America Online. Cornell Lab of Ornithology, Ithaca.Melville, D.S. and Shortridge, K.F. 2006. Migratory waterbirds and avian influenza in the East Asian-Australasian Flyway with particular reference to the 2003-2004 H5N1 outbreak. In: Boere, G., Galbraith, C. and Stroud, D. (ed.), Waterbirds around the world, pp. 432-438. The Stationary Office, Edinburgh, UK.Scott, D.A. and Rose, P.M. 1996. Atlas of Anatidae populations in Africa and western Eurasia. Wetlands International, Wageningen, Netherlands.Snow, D.W. and Perrins, C.M. 1998. The Birds of the Western Palearctic vol. 1: Non-Passerines. Oxford University Press, Oxford.

Map (see overleaf)