Jets of water, rubber snakes, loud noises and early morning patrols are used to deter tcockies from chipping away at decks, fences, window frames and roof tiles.

Since 2001, Kate Gustke has been tormented by as many as 70 cockatoos at a time landing on her terracotta roof. "It's a big problem. Cockatoos have a great game picking at the mortar - then it rolls off the roof and into the gutters."

The Department of Sustainability's wildlife management project leader, Ian Temby, said part of the problem was people feeding cockatoos, which caused them to hang around.

"Cockatoos spend much of their time [in the wild] looking for food and feeding gradually over the day. If they are given all their food requirements at once, as when people give them seed, they are left with a great deal of idle time.

"During this idle time, they alleviate boredom and condition their beaks by chewing on soft wood such as window frames, verandahs and outdoor furniture."

Ms Gustke backed the call to stop feeding wild birds. "The cost to the environment and to people's properties is unacceptable."