Pinguinus impennis
great auk

The last great auk was seen in 1852 off the Newfoundland Banks. They were extinct in the western Atlantic before 1800 and persisted a bit longer in some parts of the eastern Atlantic and off the coast of Iceland. They lived and bred on scattered, offshore islands in the northern Atlantic in recorded history, although it is possible they once occurred on continental coastlines but were extirpated from those areas earlier. They were found from Canada, Greenland, and Iceland to the British Isles and Scandinavia. Colonies in the western Atlantic may have been less numerous than in the eastern Atlantic. Archeological records indicate they once occurred as far south as southern Spain and New England in the United States, Pleistocene records indicate great auks occurred as far south as Italy and other parts of the Mediterranean. Great auks became extinct before any natural history studies were conducted, so little is known about their lives except for a few studies of lone, captive birds and the casual records of mariners. (Bengston, 1984; BirdLife International 2008, 2009)

In recorded history, great auks were found breeding only on isolated, rocky islands in the North Atlantic. They foraged in the open ocean when not breeding. (Bengston, 1984; BirdLife International 2008, 2009)

Great auks were large, flightless seabirds. They were similar in overall appearance to their smaller relatives in the family Alcidae, but much larger and with greatly reduced wings, reflecting their flightlessness. Great auks are widely considered the northern Atlantic ecological corollary to the Antarctic penguins. Great auks stood 70 cm tall and weighed up to 5 kg. They had black plumage dorsally, with white breasts, bellies, and undertail coverts. Their wings had a white trailing edge and there was a large white patch in front of each eye. Their bills were robust and ridged, like other alcids, and their gape was bright yellow. Their reduced wings were approximately the size of those of razorbills and were used to propel themselves underwater during dives. They are said to have been excellent swimmers, able to evade capture by people in boats. Analysis of bones from midden sites indicates that there may have been some geographical variation in morphology. (Bengston, 1984; BirdLife International 2008, 2009)

There are no reported of mating behaviors. Based on patterns of parental investment, great auks were monogamous and may have retained mates over many successive years. (Bengston, 1984)

Because they couldn't fly, potential breeding sites had to be accessible from the sea so that great auks could land and walk from the shore to a nesting site. They bred in dense congregations in nesting colonies but colonies seem to have relatively fewer birds than seabirds with smaller body sizes. They are thought to have bred from May through June, during a breeding window of approximately 6 to 7 weeks. However, other records indicate breeding occurring later, into August. This could represent geographic variation, re-nesting, or inaccurate observations. Females laid a single egg up to 84 by 140 mm in size. Incubation time is estimated at 44 days. Great auks may have had an exceptionally rapid hatchling development stage, fledging in as little as 9 days. This is supported by the fact that there are few or now descriptions of great auk hatchlings or hatchlings held in collections. It is possible that this rapid hatching to fledging period was followed by parental care on the water, where the family could forage and fulfill their high energy needs. Estimates suggest they may have taken 4 to 7 years to reach sexual maturity. (Bengston, 1984)

Females invested heavily in large, yolk-rich eggs and it is thought that great auks hatched at a fairly precocial state. Both parents developed brood patches, so incubated eggs and brooded their young. They probably alternated egg and hatchling tending duties, as in other seabirds. Time to fledging is estimated to be very short, but a post-fledging period of parental investment at sea is possible. (Bengston, 1984)

As in other large seabirds, annual survival is thought to have been relatively high. Estimated lifespan was from 20 to 25 years. (Bengston, 1984)

Great auks are thought to have spent most of their time at sea outside of the breeding season, when they would be found at breeding colonies on isolated, rocky islands and sea stacks. They were social, foraging in small groups and breeding together in colonies. Anecdotes suggest that they may have engaged in some kinds of visual displays, including head shaking and bowing and presenting their bright yellow gapes. (Bengston, 1984)

There are no estimates of home range size in the literature, although they are thought to have ranged widely outside of the breeding season.

Observations suggest great auks may have used visual displays in communication. Sounds are not described. (Bengston, 1984)

Great auk adults dove for fish and young birds are thought to have eaten zookplanton or smaller fish. Their morphology and flightlessness indicate they were highly specialized piscivores as adults. An analysis of the fish bones associated with great auk bones from middens indicate that they ate fish from 140 to 190 mm long, including menhaden (Brevoortia tyrannus), shad (Alosa species), capelin (Mallotus villosus), 3-spined sticklebacks (Gasterosteus aculeatus aculeatus), striped sea bass (Morone saxatilis), and flatish (Pleuronectidae). Based on these evidence, some researchers have suggested that great auks fed mainly in shallow waters (up to 18 m) within 2 km of shore and chose primarily large prey (70 to 190 mm, up to 300 mm). They seem to have preferred fish with high fat content. (Bengston, 1984; BirdLife International 2008, 2009)

Great auks were preyed on by humans. Other natural predators are not known. (Bengston, 1984; BirdLife International 2008, 2009)

Great auks were specialized predators of larger fish in the northern Atlantic. (Bengston, 1984)

Great auk bones are common in coastal middens throughout Europe and the Mediterranean dating from 13,000 to 2,000 years before present. Great auks were intensively exploited for food and fuel by mariners in search of fresh meat. Their fat was also rendered and used as fuel. (Bengston, 1984)

There are no adverse effects of great auks on humans.

Great auks are presumed to have become extinct in 1852, the last date that a wild bird was observed. The last known breeding pair was killed in 1844 in Iceland. Great auks, and their eggs and young, were relentlessly exploited for food and fuel. Like other flightless birds with few or no natural predators, such as dodos (Raphus cucullatus), great auks were docile and ungainly on land. They could not fly and could only walk at about the pace of a human walking. They did not exhibit fear when approached and were therefore easily captured and dispatched. Mariners raided nesting colonies and took birds and eggs by the thousands to eat fresh, render for fuel, or salt for later consumption. The last two birds killed in Iceland were preserved and are held in the Museum of Zoology in Copenhagen, Denmark. There is little doubt that they were hunted to extinction by humans, although there is a possibility that their numbers and range were declining previous to that as a result of environmental changes that reduced the number of appropriate islands for breeding and altered prey abundance. Prehistoric human hunters seem to have sustainably hunted great auks and some modern human populations imposed regulations to moderate the effect of their harvesting on populations. (Bengston, 1984; BirdLife International 2008, 2009)

Great auks were also known as "garefowl" and were previously known under the name Alca impennis. (Bengston, 1984)