An Arctic-breeding sea duck that spends winter along coasts and on large lakes, where it dives for aquatic animals.
Adult males have long, slender tail plumes. Females and young males lack these plumes, and the male's plumage changes greatly between summer and winter.
Female long-tailed ducks breeding in the western Russian Arctic tend to use wintering areas at similar east–west positions across years. Birds leaving the same breeding area spread across different marine wintering areas, with individuals showing repeatable destinations within that spread.
Small loggers were fitted to females at three Russian Arctic sites in 2017 and 2018. Movements were analysed for 65 females whose devices were recovered. Light measurements estimated location, while water conductivity helped distinguish the Baltic Sea from waters outside it. Of 28 birds followed for at least two winters, 26 wintered in the Baltic in consecutive years and two stayed outside it in consecutive years.
The wintering period lasted about seven months on average. In spring, most females stopped in Arctic marine waters before returning to freshwater breeding lakes and ponds. Their annual journeys link a long stay on winter seas with marine spring staging areas and freshwater summer habitats.
An extinction-risk assessment has not been added yet.
For long-tailed ducks breeding in western Russia, both the Baltic wintering grounds and White Sea migration staging areas are important to conservation. The 2025 tracking paper identifies the two seas as key areas used during different parts of the annual cycle. It recommends extending winter monitoring to ice-free waters around Finland to better detect distribution changes. Conservation of this population needs to connect wintering seas with migration staging areas.