ARMED with a sharp destructive weapon Wagga's newest villains are scaling new heights to cause frustration and nuisance to the city.Throughout the central business district white cockatoos are being seen more regularly on buildings than in surrounding trees.Leaving behind bushland, the birds are replacing bark with the walls and roof of the buildings they are now calling home.The historic Council Chambers has been one of the worst-affected buildings, with Wagga City Council yesterday revealing it has implemented a bird scare in the hope of changing the behaviour of the birds.Council yesterday admitted significant damage to the old Council Chambers has been caused by the birds.Holes and leaks in the roof caused by the birds chewing, biting and sharpening their beaks became obvious in the wet weather over the past two weeks.Council said it has tried a number of methods to scare the birds, starting with a cutout of an owl before moving onto an automatic whistling alarm.Council representatives said the birds "twinge and learn quickly it there is a real danger and adapt their behaviour accordingly", but thus far the mechanical whistler is proving successful.Bob's Birdz-N-Pets owner operator and bird expert Darren Wood yesterday admitted the destruction is typical bird behaviour.He said it was difficult to curb the behaviour of the birds, particularly cockatoos, which use the buildings to wear and sharpen their beaks.Mr Wood said there is not an unusual number of birds residing in the city, and it is not uncommon behaviour for the birds to make their homes in the CBD. "It is the time of year for it," he said."They follow the river during summer which is why we see so many on the banks and then when the weather changes and it becomes colder and wetter the birds, particularly cockatoos, move in town."This is normal behaviour, particularly for cockatoos that don't mind the human presence."It is not a problem that is confined to this local area."Mr Wood suggested a spray-on product with a bitter taste, normally used to stop birds self mutilating, could be looked at as an option to stop the birds destroying buildings.