Even Woodpeckers lead to controversy.
Doubts over 'extinct' woodpecker
http://news.bbc.co.uk/2/hi/science/nature/4815424.stmScientists in the US are arguing over the identity of a bird filmed in 2004 which was heralded as the long-extinct ivory-billed woodpecker.
Researchers in Massachusetts said the interpretation of several of the bird's features was "mistaken".
However, experts at Cornell University, who identified the bird two years ago, have dismissed the new claims.
The discovery in Arkansas' Big Woods stunned ornithologists worldwide, with some comparing it to finding the dodo.