Shruggle

You really have to check out this short quicktime movie that you can see at this link. This bird can imitate sounds that it hears.. it is quite unbelievable and I would assume it was a hoax if it didn't feature someone like David Attenborough. If you want more you can find numerous examples of their sounds here, including mimicry. The bird sounds like it is laughing in the last mp3 there.