Our pal mental_floss has a really neat article about the Lazarus species, basically animals that were once thought to be extinct, until they were rediscovered.
This one to the left is the devil bird:
This diabolical ave wasn’t thought to be real until 2001. In Sri Lanka, where the Devil Bird legend originated, the bird is known as Ulama. It has a shrill shriek that sounds eerily human-like and is said to predict the death of a loved one. But when the Spot-bellied Eagle-owl was discovered seven years ago, it was quickly realized that it matched the description of the Devil Bird quite closely.
Check out the rest of the 10 creatures people didn't think existed anymore: Link - via i met a possum