Neil Calbrade

The species breeds on various shallow lakes, slow-flowing rivers and flooded riverside woods, occupying tree holes for nesting. Outside breeding season occurs on larger ice-free freshwater and brackish wetlands, including coastal waters (Carboneras, Kirwan, 2020). Its breeding range includes the boreal zone from N Fennoscandia to E Siberia, the European strongholds being in N boreal Sweden, Finland and Russia (Keller et al. 2020). 

Intra-European migrant. Winters on lakes and coasts throughout Europe, mostly NW part, Baltic and Mediterranean/ Black Sea region.

Not globally threatened but considered Vulnerable in European context (Carboneras, Kirwan, 2020).

Season of assessment

B

Population trendStable
Population size
(min-max, best estimate)		21700-34000,27200
Red List categoryLC
Franks, S., Fiedler, W., Arizaga, J., Jiguet, F., Nikolov, B., van der Jeugd, Ambrosini, R, Aizpurua, O., Bairlein, F., Clark, J., Fattorini, N, Hammond, M., Higgins, D, Levering, H., Skellorn, W., Spina, F, Thorup, K. Walker, J., Woodward, I. and Baillie, S.R. (1) (2022) Online Atlas of the movements of European bird populations. https://migrationatlas.org EURING/CMS (1) Principal investigator
Map

Overall Connectivity for Smew

General movement pattern follows NE – SW direction. Birds breeding in N Fennoscandia move S towards Baltic Sea region and SW towards Denmark, C Europe and Atlantic Coast of W Europe. N Russian breeders (both from N Europe and W Siberia) travel SW to W Europe (The Netherlands) as well, taking much longer routes. Birds wintering in the Black Sea and E Mediterranean region originate from NE Europe, while those in Caspian Sea region – from W Siberia (Keller et al. 2020).

Birds ringed as juveniles in N Finland and subsequently found (couple of years later) during the breeding season in NW Russia suggest some degree of low breeding site fidelity.

Some separation of the sexes on the wintering grounds, with males being more abundant in S Baltic Sea region, and females and immatures dominating the flocks further S and W (Snow, Perrins, 1998).

Recoveries by Condition for Smew

Protected species in Europe. Most encounters obtained during the breeding season in early summer – ca. 92% in Jun. About 90% of all encounters recorded during the last 10-year period (2009-2018). The bulk of encounters from 1991 to nowadays (ca. 95%) comes from alive birds, based on ringing recoveries; the remainder consisted of both dead birds (shot, other reasons) and unknown cases. Recoveries obtained as a result of direct shooting were more frequent in 1961-1990 (ca. 38% out of a small sample of 21 cases).

Very few recoveries prior to 1990. About 97% of all encounters come from N Europe.

Annual Movements for Smew

Post-breeding movements of the Fennoscandian population start as early as late Aug, more often in Sep and by Oct the breeding grounds are already left; the wintering grounds in the region of Baltic Sea are reached Nov-Dec, while those in W Europe in Dec-Jan. The return migration in spring becomes noticeable in Mar, the birds are back to their breeding areas in Apr-May. Autumn migration timing of the birds breeding in NE Europe apparently similar, they have been encountered during winter in the Netherlands in Dec-Jan.

Single birds remain in their wintering areas until Apr-May, immatures can remain at lower latitudes throughout the first summer (Snow, Perrins, 1998).

After mating males moult close to their breeding grounds, gathering in big flocks (Madge, Burn, 1988).

Small number of non-breeding birds moult S of the breeding areas (Snow, Perrins, 1998).

Connectivity by Month by Region for Smew

Breeding birds from Fennoscandia are encountered from late autumn until early spring in English Channel, North Sea region, E Germany and Baltic Sea region. A number of birds ringed in the Netherlands during the winter (Dec-Jan) are subsequently encountered in NE Europe and NW Siberia, either during the breeding season or post-breeding dispersal.

Main wintering areas in Europe are considered the coastal zone of The Netherlands, Baltic Sea and Black Sea regions (Carboneras, Kirwan, 2020), the populations often subject to hard winter movements (Scott, Rose, 1996).

Recent study suggested a shift in wintering distribution within Europe in NE direction. Lacking ringing recoveries from SE Europe (Pavón-Jordan et al. 2015).

Boris Nikolov

References

Statistics Map
N records N individuals N recoveries
Mapped data*
Total available data
*Mapped data include only distant (>= 50 km) recoveries
References Map
1998 . The Birds of the Western Palearctic. Concise Edition. Volume 1. Non-passerines. Oxford University Press, Oxford, UKEditor(s): Snow, D. W., Perrins, C. M.
2020 . European Breeding Bird Atlas 2: Distribution, Abundance and Change. European Bird Census Council & Lynx Edicions, BarcelonaEditor(s): Keller, V., S. Herrando, P. Voříšek, et al.
Carboneras, C., G. M. Kirwan 2020 . Smew (Mergellus albellus), version 1.0. In Birds of the World Link to Article (DOI: https://doi.org/10.2173/bow.smew.01) Cornell Lab of Ornithology, Ithaca, NY, USA
Madge, S., Burn, H. 1988 . Wildfowl. Christopher Helm, London
Scott, D. A., Rose, P. M. 1996 . Atlas of Anatidae Populations in Africa and Western Eurasia. Wetlands International , Wageningen, The Netherlands

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