The lyrebird can mimic a camera shutter, a chainsaw, monkeys, and 20 other species of birds it hears in the forest. This is truly spectacular; you should watch the video, about halfway through the video is when it gets good.
It’s the green heron (Butorides virescens), a denizen of North and Central American wetlands and an accomplished fisherman. They are sit-and-wait predators, perching motionless on the bank or on a tree, ready to grab a fish by striking out with their amazingly long necks.
The Lyrebird (start watching the video from 1:25 onwards). A bird with an unreal capability of mimicking natural and artificial sounds. Here's another video of one: http://www.youtube.com/watch?v=WeQjkQpeJwY And more info here: http://en.wikipedia.org/wiki/Lyrebird