Steller's Eider

The most endangered seaduck in Europe

Steller’s Eider (Polysticta stelleri), is a good reason to visit Saaremaa in winter. The coast of our island is the most important wintering area for Steller’s Eider around the Baltic Sea.

These eye-catching birds arrive in December and leave around the beginning of April. The best time to observe Steller’s Eider is January and February when congregations may reach 1000 birds or even more. Birds form dense flocks where they behave synchronously, especially when diving.

Importance of the Baltic Sea

The number of Steller’s Elders wintering in North-west Europe has been estimated at 10,000 – 15,000 birds (Delany & Scott 2006). The population has been in decline since the early 1990’es, with an annual rate of 15% (Zydelis et al. 2006) between 1996 and 2003. The total number estimated for the Baltic Sea (2,300) represents a decline by 66% since 1988–1993.

Main wintering areas in the Baltic Sea

Steller’s Eiders were only recorded in three locations during the coordinated counts 2007–2009: west coasts of Saaremaa and Hiiumaa Islands (2,250), Palanga (40) and in the Archipelago Sea (13). It should be noted that the latter area covers observations from both the Archipelago Sea (8 birds), Helsinki, Pori and Rauma. The reduction in numbers is especially evident at the Palanga and in the Archipelago Sea/Åland site, but the absence of sightings outside these three main locations, e.g. on Gotland, is also striking.

Distribution in the Baltic Sea

Unlike most other species of seaducks, Steller’s Eiders prefer to winter in shallow areas close to the coast, in areas of less than 10 m water depth.

Phenology

Steller’s Eiders arrive to the Baltic Sea in November and leave in mid April – early May.
The average number of wintering Steller’s Eider Polysticta stelleri in key areas of the Baltic Sea, 2007–2009: Area indicates the size of the area in km2 , Number is the average estimated number of birds, and % compares the percentage of birds within the area with the total estimated number in the Baltic Sea.
Written by © Leho Luigujõe, Andres Kuresoo and others
Waterbird Populations and Pressures in the Baltic Sea, 2011