Birdpocalypse? Thousands of corellas cause havoc after swooping on Adelaide | Environment

They come at dawn and dusk.

At first they arrive by the tens, then the hundreds, some sticking to the treeline, others mustering on the oval.

Together they number in the thousands and in the weeks since a flock of corellas invaded Andrews Farm in Adelaide’s north – about 50 minutes from the CBD – local authorities have been in a flutter.

The little corella has historically been confined to the northeast corner of South Australia but spread with the development of agriculture and irrigation, which provided new water and food sources.

Associate professor David Paton of Adelaide University says the little corella first appeared in country towns across the state’s north half a century ago.

He says the modern day problem is not isolated to northern metropolitan Adelaide – country towns and the city centre are also playing host to flocks although they may be smaller.

“They’ve done very well because they been able to exploit the woodland areas where we tend our crops,” Paton says.

Residents of north Adelaide say the birds have been turning up in increasing numbers every year for about six months at a time. Each time they settle on a different part of Munno Para West, with contingents ranging as far north as Gawler.

Wherever they gather, signs of occupation can be found.

Trees are stripped of their leaves, plastic equipment gets chewed up and bird droppings, feathers and the occasional body of a fallen comrade litter the ground.

One Andrews Farm resident says they regularly wake up in the morning to a “sea of white” at the park across the road from their house and others speak about persistent squawking.

Paton says the birds aren’t just noisy and messy.

“It took a while to happen, but it’s at the stage now where in some places little corellas are displacing cockatoos from nesting hollows,” he says. “The flocks are quite mobile.”

Residents have heard what they thought was gunfire ring out across the neighbourhood in recent weeks, only to learn that the council were setting off fireworks in an effort to move the birds on.

From about six o’clock in the evening to eight o’clock at night the shots fire at regular intervals.

Other tactics to drive the birds out have so far included using drones to herd them away and deploying falcons as natural predators to scare them off.

While some residents said the tactics seemed to have thinned out the flock, Stephan Rudnicki is sceptical about their effectiveness.

“When the council moves them out of one area, they just go to the next,” he says. “They’re not dumb. They’re just going to relocate to somewhere else. You’re just moving the problem around.”

Paton says in the 1990s permission was given to cull the birds near Quorn, but that experiment proved that when some of the flock was killed, others would come in from elsewhere to replace them.

“In terms of how you’d manage it, the key is to get in there and disturb those birds as soon as they start to roost,” Paton says.

This is why Playford mayor Glenn Docherty is appealing to the state authorities to send in the cavalry.

Docherty has told the ABC that the birds have caused massive amounts of destruction.

“We’re very keen on the state government to take some proactive action, because council’s trying to do its best but we don’t have any legal power to manage or control them on a long-term basis,” he says.

No direct intervention appears to be planned by the Department for the Environment and Water, which said in a statement that it “works closely with landholders, offering advice and support”.

It suggests local residents should work together to move the birds on using a “variety” of measures such as noise, lights and scarecrows.

Flocks of long-billed corellas invaded regional council areas south of Perth in West Australia in January this year.

The long-billed corella was introduced to WA as an aviary bird but escapees flocked together to become a pest, crowding out local native species through competition for food sources.

In a state where memories of the 1932 Emu War remain strong, councils used fireworks, lethal gas, nets and mass shootings in an attempt to reduce population numbers.

The city of Bunbury recently announced a corella cull to remove 400 birds from the population each year for the next five years at a cost of $50,000.