Tweety, a yellow-tailed black cockatoo, was born with leucism, a rare genetic mutation that affects the pigmentation of the birds' feathers, causing them to turn completely yellow. The rarity means ...

Add Yahoo as a preferred source to see more of our stories on Google. Tweety has yellow feathers instead of black because of a gene mutation. Source: Bonorong Wildlife Sanctuary A rare cockatoo ...

The deadly Wangary bushfire 20 years ago appears to have been the final nail in the coffin for rare yellow-tailed black cockatoos on the Eyre Peninsula. There are fewer than a dozen birds left alive.