Distribution and numbers of wintering sea ducks in Swedish offshore Waters.

The first survey of seaducks covering the offshore watersof the entire Baltic was undertaken in 1992/1993, when,however, the Swedish waters were covered with relativelyfew ship surveys. The second all Baltic survey 2007–2011included extensive aerial surveys of all Swedish offshorewaters. This paper presents the Swedish data from thesetwo surveys, supplemented with data from several other butpartial surveys back to the early 1970s. The most numerouswintering seaduck in the Swedish waters was the LongtailedDuck Clangula hyemalis with an estimated populationof 1.41 million in 1992/1993, decreasing with 69% to0.44 million in 2007–2009. Hoburg bank south of Gotlandand the two Midsjö banks accounted for the vast majorityof these ducks. In 2009–2011 only small numbers of scotersMelanitta fusca and M. nigra were found in Swedish Balticwaters. The totals for the Eider Somateria molissima andRed-breasted Merganser Mergus serrator were estimated at20 000 and 8000, respectively. Larger numbers of Eiders (50000) and scoters (20 000) were found on the west coast