´óÏó´«Ã½

Audio of an Australian musk duck called Ripper saying what sounds like "you bloody fool" has been released by researchers.

The 34-year-old recording appears to be the first documented evidence of the species being able to mimic sounds.

Researcher Dr Peter Fullagar recorded Ripper in 1987 at the Tidbinbilla Nature Reserve near Canberra.

But his recordings were only recently rediscovered by Prof Carel ten Cate of Leiden University in the Netherlands.

Prof ten Cate had been researching vocal learning in birds when he came across a mysterious reference to a talking musk duck who could imitate other sounds, such as a slamming door.

"This came as a big surprise ... it remained unnoticed by researchers in the vocal learning field until now," Prof ten Cate

"That makes it a very special rediscovery."

Mimicking sounds is a rare characteristic. There is evidence of vocal learning in dolphins, whales, elephants and bats, but it does not appear to be in the nature of most mammals.

However, some birds - most famously parrots - can mimic sound.

"Although also for this group, vocal learning is rare," Prof ten Cate said.

"We know that songbirds, parrots and hummingbirds can learn to make specific sounds. This includes many species, but that is because vocal learning originated in the ancestral species of these groups."

Researchers previously assumed that vocal learning evolved in only three of the 35 orders of bird species, but thanks to Ripper, Prof ten Cate can now introduce a new order into the group.

"To observe vocal learning in such a group makes this find extra remarkable," he said.