Corella numbers in Busselton expected to drop during mating season
Wednesday, February 24, 2010 at 7:51 
Part of a flock of c.1000 LC's feeding on spilt grain around the wheat silos of Hillston. A great sight when they all take off together - and deafening! Photo: David CookBUSSELTON’s cockie population is not always the same size and could diminish soon, according to the Department of Environment and Conservation.
DEC district manager Greg Mair said in response to a query, from then shire councillor Bernie Masters, the department had been informally monitoring the size and distribution of flocks of little corellas in the Bunbury-Busselton area over the past couple of years.
They had identified four or five flocks across this area, the largest comprising about 130-150 birds.
“The birds have clearly defined seasonal behavioural and distribution patterns in the Bunbury-Busselton area, pairing off and dispersing to breed in late autumn (and) early winter, with immature and non-breeding birds remaining in a reduced flock structure during this period,” he said.
“Flocks re-form in late spring (and) early summer to feed in preferred sites over the warmer months.
“One of these sites is along the Busselton foreshore and nearby recreation fields.”
Mr Mair said control methods of the corellas were primarily designed for use in agricultural settings with the aim of protecting specific agricultural assets, such as stored grain or vulnerable crops.
Techniques, such as limiting access to food, anti-bird netting, shooting and even scaring were generally not suited to urban areas.
Mr Mair said given the Perth experience, it should be possible to substantially reduce flock sizes over two to three years, which in turn could provide a five to 10-year period before bird numbers returned to current levels.
“In the metropolitan area, set-up costs were in the order of $130,000 for the first year, with subsequent years requiring maintenance funding of $100,000 per annum.
“Unfortunately, existing DEC resources (staff and budget) within the local South West region prevent us undertaking such control programs.”