- 15–22.8 in
- 28.3 in
- 17.6–38.8 oz
- The Long-tailed Duck is one of the deepest diving ducks, and can dive as deep as 60 meters (200 feet) to forage.
- Of all diving ducks, the Long-tailed Duck spends the most time under water relative to time on the surface. When it is foraging it is submerged three to four times as much as it is on top of the water.
- Unlike most ducks, which molt twice per year, the Long-tailed Duck has three distinct plumages each year, achieved in a complex series of overlapping partial molts. The Definitive Basic Plumage is never worn in its entirety, as portions of Alternate are retained through the summer and elements of the Supplemental are acquired before all of Basic Plumage is obtained. Therefore change in plumage seems continuous from April to October.
- Unlike other waterfowl, the Long-tailed Duck wears its "breeding" or Alternate Plumage only in the winter. It gets its "nonbreeding" or Basic Plumage in the spring and wears it for the breeding season. Most other ducks wear the nonbreeding plumage only for a short period in the late summer.
Breeds in ponds, streams, and other arctic wetlands. Winters on open ocean or on large freshwater lakes.
Mostly aquatic invertebrates, including insects and crustaceans. Also some bivalves, fish, fish eggs, and plant matter.
- Clutch Size
- 5–10 eggs
- Egg Description
- Pale gray to olive.
- Condition at Hatching
- Downy and eyes open. Leave nest soon after they dry. Feed themselves immediately.
Shallow scrape in the ground, lined with willow and birch leaves and then with down. Placed at the water's edge, often on islands or peninsulas, close to other Long-tailed Duck nests.
Dives for prey on or near bottom.
The 2014 State of the Birds listed Long-tailed Duck as a Common Bird in Steep Decline. Numbers difficult to census because of offshore wintering areas. Not widely hunted. Entanglement in fishing nets killed tens of thousands of Long-tailed Ducks in the 1950s, especially in the Great Lakes; recent statistics and trends on by-catch of Long-tailed Duck have not been compiled.