© Copyright: Images: Jari Peltomäki, Jouko Lehmuskallio, M. & W. von Wright: Svenska fåglar (Kansalliskirjasto, The National Library of Finland). Recording: Jan-Erik Bruun. All rights reserved.
- Name also: Oldsquaw
- Family: Waterfowl – Anatidae
- Appearance: A small diving duck with a rounded head, a short sturdy bill. Plumage varies greatly seasonally, but wings always uniformly dark. Tail sharp and pointed, with central pair of tail feathers elongated on males to a narrow tip.
- Size: Length 39–47 cm, wingspan 65–82 cm, weight 400–860 g.
- Nest: usually near a shoreline, well concealed, lined with down.
- Breeding: 6–8 eggs laid May–June, incubated by female for 23 days. Ducklings leave nest soon after hatching and start to forage for food by themselves, though they stay together with their brood near their mother. They become more independent at the age of 5 weeks when they learn to fly.
- Distribution: Breeds beside lakes in Northern Lapland, also occasionally in Southern Lapland and along Finland’s Baltic coasts. Finnish breeding population estimated at 1,500–2,000 pairs.
- Migration: Migrates by day or night. Autumn migration September–October, returning in May. Mainly winters in the Baltic Sea Proper or the North Sea, though some birds may stay in unfrozen Finnish waters including the Archipelago Sea and any other unfrozen coastal and inland waters.
- Diet: Invertebrates.
- Calls: A loud “a-al-li” audible over long distances. In large flocks birds may sing together in chorus.
- Endangerment: Near threatened, protected. Long-tailed Ducks may be hunted in Finland, but they may be hard for hunters to identify, since their plumage varies more than that of any other duck, seasonally, by sex, and by age. European red list status (also globally) Vulnerable.
Males have uniquely long tail feathers (the central tail feathers of mature males can be as long as 18.8–25.4 cm.) In their winter plumage adult males are mainly white, especially on the head and neck, but with distinctive blackish cheek patches. In their summer plumage males are much darker, with dark brown heads and necks and large white eye patches. Females lack elongated tail feathers and have plumage somewhat similar to males, but with duller brown markings and fewer bright white patches.
In flight Long-tailed Ducks in all plumages can be recognised by their tapering uniformly dark wings and their white-edged black tails. Their flight is rapid, with a characteristic wing-beat dipping lower below the horizontal and lifting less above the horizontal than any other waterfowl species. Their legs are blue-grey (males) or greenish grey (females) with dark webs. Males have black beaks with a reddish band behind the tip, and their irises are red. Females have dark grey beaks and yellow irises.