Extinction of the Great Auk

The Little Ice Age may have reduced the population of the Great Auk by exposing more of their breeding islands to predation by Polar Bears, but massive exploitation for their down drastically reduced the population. By the mid-16th century, the nesting colonies along the European side of the Atlantic were nearly all eliminated by humans killing this bird for its down, which was used to make pillows.

In 1553, the auk received its first official protection, and in 1794 Great Britain banned the killing of this species for its feathers. In St. John's, individuals violating a 1775 law banning hunting the Great Auk for its feathers or eggs were publicly flogged, though hunting for use as fishing bait was still permitted...

If you come for their Feathers you do not give yourself the trouble of killing them, but lay hold of one and pluck the best of the Feathers. You then turn the poor Penguin adrift, with his skin half naked and torn off, to perish at his leasure. This is not a very humane method but it is the common practize. While you abide on this island you are in the constant practize of horrid cruelties for you not only skin them Alive, but you burn them Alive also to cook their Bodies with. You take a kettle with you into which you put a Penguin or two, you kindle a fire under it, and this fire is absolutely made of the unfortunate Penguins themselves. Their bodys being oily soon produce a Flame; there is no wood on the island.

It was on the islet of Stac an Armin, St Kilda, Scotland, in July 1840, that the last Great Auk seen in the British Isles was caught and killed. Three men from St Kilda caught a single "garefowl", noticing its little wings and the large white spot on its head. They tied it up and kept it alive for three days, until a large storm arose. Believing that the auk was a witch and the cause of the storm, they then killed it by beating it with a stick.

Text and image from the Wikipedia entry, where there is much more information.