The Least Auklet is a very small seabird that breeds on islands in the Bering Sea and Alaska. It nests in rock crevices and eats small animals from the sea.
In summer, the underparts vary from white to spotted to dark gray. In winter the underparts are white, so its appearance changes with the season.
It dives from the sea surface to feed on tiny crustaceans such as copepods. At breeding sites it nests in rock crevices.
It lays one egg, and both sexes incubate it for 25–39 days, usually about 30 days. Both parents carry food to the nest in a throat pouch. The chick leaves the nest 25–33 days after hatching.
An extinction-risk assessment has not been added yet.