Australia's crafty cockatoos are in an "innovation race" with humans, scientists say. Birds and humans are battling it out over rubbish bins.
The pretty white birds have surprised scientists by inventing an ingenious way to open rubbish bin lids in Sydney.
The birds' and humans' behaviour is a new "innovation race" between the two species.
The small town of Stanwell Park near Sydney is on the front line of the battle of the bins.
"If we don't close the bin right after throwing out the rubbish, the birds will be in there," says Ana Culic, the manager of the town's Loaf Cafe. "Cockatoos and rubbish everywhere."
Her family had tried scaring cockatoos away with owl statues, but it didn't work. Then they tried putting bricks on the bin lids, but the cockatoos learned to remove them. Finally, they put a lock on the bin.
"They're evolving. Five years ago, they didn't know how to open bins, so they're figuring stuff out," says the cafe's chef, Matt Hoddo.
Nearby, Skie Jones says he is using an elastic cord to hold down the lid of his bin, after the birds worked out how to remove a brick and then a larger rock. "I will have to use a lock," he says. "It's only a matter of time."
A cockatoo can open a bin by holding the lid up with its beak while standing near the front edge. Then, with the lid still in its beak, it shuffles backward towards the hinge, forcing the lid higher until it flips open.
The scientists say the knowledge of this technique has spread as other birds looked on, creating local bird "traditions".
Humans learned to adapt. But then so did the cockatoos. "Bricks seemed to work for a while but cockatoos got too clever," one resident says.
Despite the mess, many residents still like the birds. "We call them the rats of the sky because they just love food," says Katherine Erskine. "They are beautiful and they're really noisy, but I do love them."
Five things to know about
1. A cockatoo is a kind of parrot. There are 21 species of cockatoo.
2. Cockatoos are mostly found in Southeast Asia (the Philippines, Indonesia and Papua New Guinea) and Australia.
3. The name "cockatoo" comes from the Malay name for these birds, "kakak tua" (meaning "older sibling").
4. Cockatoos are easy to recognise from their showy crests on top of their heads. They have curved, strong bills and strong claws. They like to eat seeds, tubers, fruit, flowers and insects. They feed during the daytime.
5. Cockatoos like to make their nests in holes in trees. But they can't make these holes themselves, so they have to search for holes made by branches breaking off of trees.
