Arthur A. Allen / CLO
The largest of the woodpeckers north of Mexico and the third largest in the world, the Ivory-billed Woodpecker was a bird of old-growth forests of the Southeast. Destruction of its forest habitat caused severe population declines in the 1800s, and only a handful of birds remained into the 20th century. It was thought to have gone extinct in the middle of the twentieth century. The bird was rediscovered in the "Big Woods" region of eastern Arkansas in 2005, but has proven difficult to relocate since then. For a full account of this story, including conservation efforts, go here.