Glossy black cockatoo under threat (Dr Guy Castley)An unlikely culprit is threatening the habitat and breeding of the glossy-black cockatoo on Kangaroo Island.
Motion sensor cameras installed in trees of the Western River area show possums are getting into hollows where the cockatoos nest.
Project officer with the South Australian Environment Department, Mike Barth, said protective collars had been put around trunks of some of the eucalypts.
But he said the possums were climbing up nearby trees without collars and jumping across to the cockatoo nests.
"They only lay a single egg and so when a possum goes into the nest it basically takes that one egg, or even at the chick stage it can take a chick as well," he said.
"And that can be the end of that breeding for that pair that year."
Mr Barth said although possums were the main predators, other native birds were also causing problems.
"You have other things out there, competitors and things that cause disturbance at the nests, like the galahs and the little corellas as well," he said.
He said corellas had been known to kill cockatoo chicks and take over the hollow.
Control effort
The department is continuing a control program to prevent such deaths.
At last count, there was just over 360 of the endangered birds on Kangaroo Island and about 40 nests.
But Mr Barth was confident of eventually seeing a population of between 600 and 700 birds.
He hoped the cockatoo numbers would steadily increase over the next couple of decades.
"With this particular species being long-lived and having such a low reproductive rate, things don't happen quickly as far as recovery," he said.
"We have to be committed for quite a long time before we [will] see a big population increase."
In an effort to boost the numbers, volunteers are helping department staff plant the glossy black’s sole food source – drooping sheoak trees.
It is planned to plant hundred of seedlings this weekend.
The teams will also monitor nests and make another count of cockatoo numbers.