More than 150 birds roost at the Perry Lakes site, corner of Underwood Avenue and Brockway Road, and near Hollywood Hospital on Aberdare Road, Shenton Park.
Western suburbs count organiser Margaret Owen said the birds were attracted to trees more than eight metres high, close to daily water and feed sources, including nectar currently made by banksia at the Underwood Avenue site where the University of WA proposes to build homes.
The Federal Government will decide on the proposal because several endangered species, comprising Carnaby’s and forest red-tailed black cockatoos, graceful sun-moths and rainbow bee-eaters, use the site.
The count found 157 Carnaby’s cockatoos at Perry Lakes, the same as 2013, and 114 at Hollywood, down from 183 last year.
The main threat was habitat clearing in the South West.
‘Carnaby’s cockatoos have learnt to adapt to eating pine seeds, but 22,000 hectares of pines in the Gnangara, Pinjar and Yanchep plantations will be removed without replacement,’ Mrs Owen said.
This month’s count test if population fall in the Swan Region is a trend and a complete analysis of figures from across the South-West is expected in June.