As opposed to many other migratory birds, long-tailed ducks arrive on the coasts and islands of West Estonia for wintering and migrate to the tundra region to nest and raise their chicks on the shores of the Arctic Ocean and large lakes. The chicks, 5–12 of them in a clutch, are able to move around and feed themselves shortly after hatching.
Long-tailed ducks feed mainly on molluscs, crustaceans and smaller fish, catching them by diving.
Courtship begins already in January and involves loud vocalization of the males. Their call sounds like ow-ow-owoolik .