Alle alle (Linnaeus, 1758)

Taxonomy and Naming

This species, the little auk, has the scientific name Alle alle (Linnaeus, 1758).

Size Comparison to Related Species

It is the only Atlantic auk of its size, measuring half the size of the Atlantic puffin.

Standard Body Measurements

It has a total length of 19–21 cm (7.5–8.3 in), a wingspan of 34–38 cm (13–15 in), and an adult weight ranging from 130–200 g (4.6–7.1 oz).

Subspecies Size Difference

The subspecies A. a. polaris is slightly larger than the nominate subspecies.

Breeding Plumage

In breeding plumage, the head, neck, back, and wings are black, with a white trailing edge on the secondary feathers and white fringes on the scapular feathers, and the underparts are pure white.

Bill and Tail Morphology

The bill is short and stubby, and the species has a small, rounded black tail.

Winter Plumage

In winter plumage, the lower face and fore neck turn white.

Vocalizations

At breeding colonies, little auks make a range of twitter and cackling calls, but they are typically silent when at sea.

Flight Characteristics

Their flight is fast and direct, with rapid whirring wing beats, a trait shaped by their short wings.

Foraging Method

Like other auks, these birds forage for food by swimming underwater.

Primary Diet and Prey Requirements

They mainly eat crustaceans, especially copepods: a 150 g (5.3 oz) little auk needs around 60,000 copepods per day, which is equivalent to 30 g (1.1 oz) of dry food weight.

Secondary Prey Items

They also eat small invertebrates such as mollusks, as well as small fish.

Feeding Mechanism

Recent evidence indicates that instead of filter-feeding on planktonic prey, little auks hunt through visually guided suction-feeding.

Seasonal Foraging Locations

During the breeding season, they feed close to shorelines; in winter, they feed near ice edges and coastlines.