Happy Feet: Released penguin 'missing' after being released into wild
13 September 2011 Last updated at 07:55 BST
Wildlife experts have lost contact with Happy Feet, the penguin that they released back into the wild last week.
They had nursed the Emperor Penguin back to health after he was discovered on a beach in New Zealand over the summer.
He was released five days ago with a satellite transmitter glued to his feathers but now they are not sure whether Happy Feet has died, or whether his transmitter has just fallen off.