The Great auk or garefowl was a flightless seabird and has been extinct since 1844. Similar in appearance to smaller relatives in the Alcidae family, they were excellent swimmers and could evade capture by people hunting them in boats. Utterly defenseless, they were killed for food and bait by hunters, especially during the early 1800s. Huge numbers of them were caught, and the last known individuals were killed at Eldey Island, Iceland in June 1844. About 80 specimens and about the same number of their eggs have been preserved in museums. Razor-billed auks or razorbills are their closest living relatives.
The Great auk used to live in the North Atlantic from Canada, Iceland and Greenland to Scandinavia, the British Isles, France and northern Spain. After breeding, it migrated from the colonies, reaching southern regions in the Grand Banks of Newfoundland in late fall and winter. Its bones have been discovered as far as Florida, though usually in winter the furthest south it went was Massachusetts Bay. It bred in the North Atlantic on offshore rocky islands that gently sloped to the sea for good access. It foraged in cold waters in the open ocean.
It is thought that Great auks mostly spent their time at sea. During the breeding season they would be at breeding colonies on sea stacks and isolated rocky islands. Being social birds, they foraged in small groups. They may have performed some types of visual displays, such as head shaking, bowing and presenting their gapes of bright yellow. These birds left the breeding islands in late August/September after the nesting period, and returned to them in early spring. Great auks were flightless, but were very good swimmers and divers. On land they were clumsy when walking in an upright posture, due to their legs being placed so far back on their body. Great auks made low croaks and hoarse screams, their voice generally being louder and deeper than the razorbill’s. In addition, they used visual displays for communication.
Great auks were highly specialized piscivores, usually eating fish that were 140/190 mm long, and favoring a high fat content. The young may have eaten smaller fish or zooplankton.
Great auks were monogamous, usually forming long-term pair bonds. Visual displays of head shaking and bowing during courtship were thought to show off the black-and-white pattern on their heads and their bright yellow gape. Their breeding season was from May to June or August. They bred in colonies on remote rocky islands, tightly packed with pairs close together. A single elongated egg was laid directly on bare ground. Both parents incubated the egg for 39-44 days, taking turns. Chicks hatched in June and later. The gray downy chick was fed by both its parents, leaving the nest site at just 2-3 weeks of age, to reach the sea in the middle of July, still dependent on its parents for food. This species reached maturity when it was 4-7 years old.
The Great auk is classified as Extinct (EX) on the IUCN Red List. Excessive hunting by humans was the main reason for its extinction, although it is possible that range and population were declining as a result of weather conditions and environment changes, with a reduction in the availability of food and suitable islands for nesting. Once their population was reduced by hunting to a dangerously low level, these birds were sought by collectors, including museums, and this final demand drove them into extinction.