Happy hunting grounds ... In Holt, a quartet of white cockatoos enjoy a snack and a convenient perch. Photo: Colleen Petch
After a summer of breeding Canberra's white cockatoos are back in town, tearing into mischief.
Some birdos reckon the full autumn influx is yet to hit, when flocks of cockatoos crowd road edges to grub out corms and rootlets.
Many street and garden trees are already being trashed.
Canberra naturalist and author Ian Fraser says cockatoos' bills grow incessantly, so they need to keep grinding them down, which explains why some like to chew on clothes pegs and fascia boards of buildings.
Few things are beyond the reach of cockies, even street light covers.
''They are curious too. They investigate. If something is sealed, they'll try to see what's behind it in case there is something to eat there,'' Mr Fraser said.
''What I used to see regularly in McCaughey Street in Turner, I'd drive down and see most of (the light fittings) hanging down.''
Territory and Municipal Services is fitting new streetlights in the ACT with a cockatoo-proof clip that prevented birds from opening them.
About 5000 lights still have the old latch system and at the end of their usefulness will be replaced with new light fittings.
Mr Fraser said much of the cockatoo's diet comprised of seeds that they stored temporarily in their crop, a specialised organ that worked like an internal sack.
''Feeding on the ground is dangerous, so by having this crop they wolf down their feeds, get them into the crop and then fly away somewhere to digest them.
''That gives them plenty of time to loaf around with nothing much to do basically.''
He said in summer the cockatoos mostly left town to breed in hollow paddock trees around Canberra.
Territory and Municipal Services manager of urban treescapes Michael Brice said at this time of the year the cockatoos' favourite trees were Chinese pistachios. They chew off branches, take off the berries and return for more, dropping plenty of foliage on to the ground. ''It's not massive damage. Smaller trees can be disfigured,'' Mr Brice said.
He said the galahs' habit of tearing strips of bark off red gums could be more problematic and contributed to dieback. Galahs also got into the forks of white stemmed gums and chewed them out.
While white cockatoos have no problem finding food in Canberra, black ones aren't so fortunate.
On March 4 in Queanbeyan a project will be launched to grow more food-producing trees for glossy black cockatoos.
Tony Robinson, of the landscape group Kosciuszko 2 Coast, is co-ordinating the project to plant 10,000 trees.
He said glossy black cockatoos were specialist feeders, preferring the Allocasuarina species (sheoaks).
''They will eat grubs and that sort of thing,'' Mr Robinson said.
They are specialists, whereas the white cockatoos will eat anything - including your apples and fruit trees.
''There's a big stand of drooping sheoaks on Mount Majura and they have been seen on that site and other stands around Canberra.''