Least Auklet

The least auklet, Aethia pusilla, is a diminutive seabird and holds the title of the smallest member of the auk family. This species boasts the distinction of being North America's most populous seabird and ranks among the world's most numerous, with an estimated nine million individuals fluttering across the skies.

Identification Tips

When observing these charming birds, one will note their compact size and the characteristic auk silhouette. Their plumage is predominantly dark above with a white underside, providing a stark contrast that is often visible even at a distance.

Habitat

The least auklet is a creature of the marine environment, favoring the chilly waters of the northern latitudes. They are most at home on the islands off the coasts of Alaska and Siberia, where they find sanctuary for breeding.

Distribution

During the breeding season, these birds congregate in vast numbers on the Aleutian Islands, St. Lawrence Island, and Little Diomede Island. In the winter months, they remain close to the ice sheet's edge, though the exact parameters of this icy boundary remain somewhat enigmatic.

Behaviour

Least auklets are known for their highly social nature, forming colossal colonies that can number up to a million individuals. They exhibit a remarkable ability to dive and "fly" underwater using their wings for propulsion, a skill they employ in pursuit of their prey.

Diet and Feeding

The diet of the least auklet is primarily composed of calanoid copepods, especially those from the genus Neocalanus. They also partake in euphausiids, pteropods, and other zooplankton species. These birds are adept at locating areas where upwelling and thermoclines cause their prey to cluster, making for efficient hunting. Their appetite is prodigious, consuming an astonishing 86% of their body weight each day.

Breeding

Breeding season witnesses the transformation of rocky crevices into nurseries, as least auklets lay a single egg per pair. The egg is incubated for a month, culminating in the emergence of a semi-precocial chick adorned in black down. Both parents are diligent in their duties, sharing the responsibilities of incubation, brooding, and feeding. The chicks are nourished with zooplankton, delivered from a sublingual pouch, a method shared with other small auklets. Once fledged, the young are left to their own devices, capable of diving and foraging immediately.

Conservation Status

Despite the least auklet's current abundance, they are not immune to environmental threats. Oil spills pose a significant risk, and the introduction of predators such as Arctic foxes and rats to their breeding islands has led to local extinctions. Nevertheless, the IUCN currently categorizes them as a species of Least Concern, a testament to their resilience and prevailing numbers.