Question: Why did the Great Auk become extinct?
Answer: Primarily because of human exploitation for its feathers and meat.
For those of you who are unfamiliar with the great auk (Pinguinus impennis), this penguin-like creature (a product of convergent evolution) inhabited the North Atlantic Ocean in the Northern Hemisphere, and became extinct mid-way through the 1800s. The great auk was intensely hunted by humans in European waters for their down feathers, which were actually used in both pillows and hats, as well as for food. (Not the down feathers, mind you, but the meat of the bird and its eggs). It wasn't until 1553, around the time that the nesting sites of the great auk had been all but eliminated on the European side of the Atlantic, that the great auk first became officially protected. In 1775, people who had broken a law forbidding people from killing the great auk for its feathers were actually beaten publicly!
Following the local extinction (an extinction of a population of animals in one place, but not an extinction of the animal species as a whole) of the great auk in Greenland in 1815, the sole remaining breeding site of the great auk was a small, volcanic island. Off of the coast of Iceland, the island was dubbed "Geirfuglasker," after the Norse term for "great auk," "Geirfugl." In 1830, however, the great auk population on Geirfuglasker came under siege by two elemental forces that it had no hopes of combating: an underwater volcanic eruption and a subsequent earthquake, which combined to destroy the island, terminating most of the rest of the great auks.
Those few auks that survived relocated to the nearby island of Eldey. Eldey was quite easily accessible to man, however, and the last human-led hunt of the great auk occurred on June 3rd, 1844. On this last great hunt, a pair of these birds were killed, beaten to death, and their egg was destroyed.
The last sighting accepted by the IUCN to be legitimate was in 1852 off of the coast of Newfoundland in Canada.
The closest living relative of the great auk is believed to be the razorbill (Alca torda), seen below.