Long-tailed duck

lad. Clangula hyemalis L.
Estonian Aul

Also known as: coween, oldsquaw

Status in Estonia

Migratory and wintering bird.

Description

The long-tailed duck is a small brown, black and white duck. The head is round and the beak is short and stubby. The male bird is easily distinguished by its extremely long and thin tail feather, which can be 10–15 cm long and bent upwards. The wings are narrow, pointed and entirely dark. In the summer, the male bird’s plumage is primarily brownish-black, the side body is greyish-white, the side of the head has a white patch and the shoulder feathers are black with a rusty yellow border. In spring, the beak has a pink cross streak over the centre; in summer, it is typically entirely dark. In the autumn, the male bird’s plumage is significantly whiter. The coat, most shoulder feathers, the head and neck are white, with a dark patch on the sides of the head and neck. In winter, the male is similar to how he is in autumn, but the forehead and side of the head are pale grey-brown rather than white and the dark patch on the side of the head and neck is black rather than brownish-grey. The female bird resembles the male bird during summer, but it lacks the long tail feathers and is duller in colour. The light patch on the side of the head is smaller and less defined and there is a light streak around its neck. In the autumn and winter, the female bird has an off-white head with a black crown and a dark spot on the lower cheek and side of the neck, while the shoulder feathers are longer and edged with a brighter yellowish-brown. The juvenile resembles the female in autumn but is less dark with an even less defined patch on the side of the head and neck. It also has shorter and blunter shoulder plumage and tertials.

Size

Body length 39–47 cm, wingspan 65–82 cm, body mass 500–1100 g.

Long-tailed duck (female). Photo: Roger Erikson

Similar species

None.

Distribution

The long-tailed duck is widespread in both North America and Northern Europe. Long-tailed ducks in North America primarily breed in the Great Lakes, while in Europe they breed in tundras. They migrate south of the tundra to winter. In Europe, long-tailed ducks winter specifically along the coast of the Baltic Sea, making it their most important wintering location worldwide. In Estonia, the long-tailed duck is a migratory bird that does not breed here.

Population

It is estimated that several million long-tailed ducks migrate through Estonia. During warmer winters, 100,000–500,000 individuals winter in Estonian coastal waters.

Occurrence in Estonia

It is rarely seen during the summer; it is most common during the spring and autumn migration. They arrive in Estonia in October and November and return to colder climates in May.

Diet

It feeds on marine invertebrates, particularly molluscs. Long-tailed ducks are one of the deeper-diving ducks, capable of finding food as deep as 60 metres. However, it primarily feeds below the water’s surface, swimming at depths of up to 10 metres.

Habitat

The long-tailed duck mostly inhabits the open sea. During migration, it can be found on lakes and rivers as well as ponds in raised bogs.

Nesting

It does not breed in Estonia but rather in the tundra zone. Pairs form in the winter or during spring migration. It builds a nest near a body of water and lays 6–10 greenish or cream-coloured eggs. The female incubates the eggs for 24–29 days. The chicks can instantly move around and forage for food on their own. Chicks can fly after 35–40 days.

Conservation status and protection

The long-tailed duck is not under protection. Adult long-tailed ducks have only sea predators as natural enemies, while chicks and eggs are especially vulnerable to gulls. Many long-tailed ducks die in fishermen’s seines and thousands more die as a result of oil spills.

Distribution and population in Lääne County

From late autumn to spring, long-tailed duck is one of the most common sea ducks in Lääne County. In spring, long-tailed ducks migrate in Virtsu and Puhtu, while in October, the migration of tens of thousands of long-tailed ducks can be seen on Cape Põõsaspea.
Thousands of long-tailed ducks winter along the county’s northwest coast. The best places to see them are at Port Dirhami or Cape Põõsaspea. Many bigger long-tailed duck flocks congregate to eat on offshore shallows, where they are difficult to see even with good vision. The Neugrundi shallow in Osmussaare is one of those important winter feeding areas.