Least Auklet
Aethia pusilla

Conservation status | Abundant, with North American population estimated at 9 million in late 1980s. Accurate counts very difficult, however, so trends in numbers hard to detect. Many populations have disappeared or declined after introduction of foxes or rats to their islands. Accidental introduction of rats to additional islands may be single greatest threat. |
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Family | Auks, Murres, Puffins |
Habitat | Ocean, northern islands. May forage close to shore or far out at sea. Favors areas with turbulent water, upwellings, strong gradients of water temperature or salinity, edges of currents, or tide rips. Nests on islands in boulder fields, talus slopes, lava flows, rock crevices. |
Photo Gallery
Feeding Behavior
Forages while swimming underwater. Fast and agile underwater but probably not able to dive very deep.
Eggs
One. White, becoming nest-stained. Incubation is by both sexes, 25-39 days, usually about 30 days. Young: Both parents feed young, bringing food to nest in throat pouch. Young develops faster than young of most auks, leaves nest 25-33 days after hatching.
Young
Both parents feed young, bringing food to nest in throat pouch. Young develops faster than young of most auks, leaves nest 25-33 days after hatching.
Diet
Crustaceans and other marine invertebrates. Diet in summer is small creatures that occur in swarms in cold waters, mostly very small crustaceans known as calanoid copepods, also some euphausiid shrimp, amphipods, others. Diet at other seasons not well known.
Nesting
First breeds at age of 3 years. In courtship, male perches upright and makes chattering calls; female approaches in exaggerated stretching and crouching postures, then both birds engage in bill-touching and chattering in duet. Pair-bond often lasts more than one season. Nest: In colonies located in talus slopes, rock piles, other areas with abundant small rock crevices for nest sites. No nest built, egg laid on bare rock, soil, or pebbles. Pair may re-use nest site for several years.
Illustration © David Allen Sibley.
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Text © Kenn Kaufman, adapted from
Lives of North American Birds
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Migration
Birds from northernmost colonies move south to evade the solid ice that surrounds their colony sites in winter. Those from Pribilof and Aleutian islands may be permanent residents in general region of colonies. Very rare stray as far south as British Columbia and Washington.

- All Seasons - Common
- All Seasons - Uncommon
- Breeding - Common
- Breeding - Uncommon
- Winter - Common
- Winter - Uncommon
- Migration - Common
- Migration - Uncommon
See a fully interactive migration map for over 450 bird species on the Bird Migration Explorer.
Learn moreSongs and Calls
Various twittering notes around breeding colonies.Learn more about this sound collection.