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Cockatoos attack

The sulphur-crested cockatoo is usually found in pairs or small parties. But in southern Australia they often congregate in large flocks of up to a hundred noisy birds. These cockie mobs can get nasty and attack trees, decks and houses in a controlled frenzy of destruction that can go on for days.

Cockatoos are most destructive in spring when they have an increased tendency to chew, especially in early spring and also in late summer. Parent cockatoos are trying to build nests in early spring. In late summer, the baby birds leave the nest and like teenagers start exploring their environment and are more likely to destroy things.

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Guess who's coming to dinner?

When the Balkins family bought western red cedar for the exterior of the house they'd lived in for 17 years in Sydney's upper North Shore they didn't expect nature to bite back.

Sue Balkin came home one day in 2001 to be told by neighbours that 150 birds had "latched" onto the family house. "And they weren't just chipping away at the timber," she says, "they were actually ripping the timber off the home and the timber railing."

"It was a nightmare," says Sue Balkin. "It was like that movie The Birds."

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Why?

There are various theories amongst experts as to why sulphur-crested cockatoos damage homes like the Balkin's. It seems we don't know for sure why the cockies attack.

"They do it because of boredom or because there's nothing else to do," says Associate Professor Lucio Filippich, an avian expert at the University of Queensland. He also says that the cockatoos use their beaks to wear them down so they don't overgrow.

Bird veterinarian Dr Michael Cannon agrees saying that sulphur-crested cockatoos will chew to keep their beaks, an important tool for everyday life, in good trim.

There are also other reasons he said. "We know that in the wild they remove bark and they'll chew things up to try and find grubs," he says. "But they are also naturally destructive, just chewing things."

Kingsley Mead of Cockatoo Control, a company which has developed an electric fencing to protect the rubber absorbers placed on the rooves of houses with solar heated swimming pools, says that it is almost as if the cockatoos "decide" to attack a property, leaving the one next door untouched. "They're pretty smart codgers," he says.

Another reason is that soft woods like western red cedar are easy to chew. "It's like soft butter to a cockatoo's bill," says Dion Hobcroft of Taronga Park Zoo who has been watching birds since the age of seven. "So it's probably quite pleasurable to chew into these soft structures."

Dr Ross Perry, self-proclaimed grandfather of the bird veterinarians, has a different theory. His view is that the sulphur-crested cockatoos are adapting to the urban environment. "It is finding out what is edible, what is not edible. Exploring that sort of thing," says Dr Perry.

However, Dr Perry doesn't discount that the sulphur-crested cockatoos could just be having a bit of fun.

"They're quite clowns, so they do have a huge sense of fun. They're a highly intelligent animal."

Fact file: When: Year round Where: Coastal Australia Other info: Feeds: Ground

Eats: Seeds, insect larvae, berries

Nest Habits: Tree hole

Flight: Uneven flap-flap-glide, sometimes swoops to land

Habitat: Most areas

Size: Approx 50 cm

Call: A loud raucous screech. Usually in flocks.

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Growing in number in Sydney

Originally the sulphur-crested cockatoo only existed west of the Great Dividing Range. "Sulphur-crested cockatoos were relatively uncommon in the '50s and '60s," says Geoff Ross from the National Parks and Wildlife Service (NPWS).

Numbers of sulphur-crested cockatoos have increased in Sydney since then and experts have various explanations as to why this has occurred.

Ross says that anecdotal evidence would suggest that sulphur-crested cockatoos and some other species of parrots are moving east to places like Sydney, away from drought restricted areas.

"We don't have any hard data on this" says Ross, "I am currently researching to try and find any correlations with increasing population size associated with drought."

Dr Perry also believes that drought has an effect. "I suspect weather change and agriculture have also made a large impact on the bird population."

Unlike other species of cockatoo, such as the endangered major mitchell cockatoo, sulphur-crested cockatoos have a natural tendency to fly over wide open spaces and therefore adapt and migrate far more readily over fields of monoculture crops which provide concentrated food sources, says Dr Perry.

But there is another factor responsible for the increase of birds in the Sydney area and that is, quite simply, the presence of humans.

"Many cockatoos escape," says Dr Perry. "They're being sold by the trappers to the Sydney market all the time in pet shops."

Bird veterinarian Dr Michael Cannon agrees: "Man has come and changed the environment and made it easier for the birds to establish here," says Dr Cannon. "They've also brought them in as pets and released them and the birds have found that they could stay."

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One vengeful trapper

One controversial theory for the dramatic increase in Sydney's sulphur crested cockatoos is that hundreds of sulphur-crested cockatoos were released in Sydney in the 1980s by a disenfranchised bird trapper who was lobbying government unsuccessfully in a petition to legally export wild-trapped cockatoos.

Dr Perry believes that the trapper's rationale for releasing these birds was: "so they would become a pest to the buildings and so forth. So that they would create an anti-cockatoo lobby within the city area."

He has no proof for this assertion however and other experts believe that the story is just an urban myth.

Ironically, even if the trapper did not release the birds in Sydney as claimed, or if the cockatoos he supposedly released did not increase numbers, his aim of creating an urban pest appears to be coming to fruition.

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Keeping them away

There are several ways you can discourage birds from attacking your property. Sulphur-crested cockatoos are a protected species, so make sure you don't harm them!

One way is to string up a kite that looks like a hawke or an eagle.

Another is to purchase a gel (from pest control companies) that makes standing uncomfortable for the birds.

Or try stringing fishing line over the area that needs protection, making it difficult for the birds to land.

Having a dog or cat in the yard can also help.

Another option is to use a high-pressure hose. "They are creatures that are aware and do recall traumatic incidents," says Professor Filippich from the University of Queensland.

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Asking them to leave

Once a flock of cockatoos have decided to attack your house getting rid of them can be a bit tricky.

The Balkin family found that the birds weren't frightened off easily. In fact, the cockatoos would wait on the electricity wires outside the house till the family left, just like the birds in the chilling scenes of Hitckcock's famous movie.

"There would have been a hundred lined up on the wires, just waiting. It was very eerie," says Sue Balkin.

In the end the Balkin family could think of no other solution than to cover the entire house with netting, purchased from the local hardware store.

Ironically, the house resembled a bird cage. "And we were living inside this cage," says Sue Balkin.

Even this did not stop the birds. "They were cutting through the netting and they were getting back in again," says Sue Balkin.

"We ended up buying a cap gun and every time they came towards the house, we would use the cap gun."

One person had to stay at home on 'cockatoo duty'. Eventually the birds moved on. However, once they stopped attacking the Balkins home, they started destroying other houses in the area.

For really severe problems, Geoff Ross from the National Parks and Wildlife Service (NPWS) recommends getting an occupier's licence. This licence is issued by NPWS and costs nothing. "An occupier's licence allows the landholder to remove wildlife without being prosecuted," says Ross.

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Final lesson

One lesson Sue Balkin has learnt is that despite their own pearly white plumage, sulphur-crested cockatoos do not like the colour white.

"My next door neighbour was never attacked. She's got white railing on her timber," she explains. "The green netting I originally put on the house didn't deter them but once I bought the white netting, they stopped."

Maybe if a re-make of Hitchcock's masterpiece is ever considered, someone should suggest using sulphur-crested cockatoos. At least then, art could imitate life, instead of the other way round.

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Further information

Cockatoo facts

Backyard Birdwatch

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