Carnaby’s Black Cockatoo (Calyptorhynchus latirostris) family group. Photo: SandraALMOST 20 Carnaby’s black cockatoos have died since January after showing signs of organophosphate poisoning.

Perth Zoo has reported 19 deaths of the endangered birds after they were presented with signs of poisoning.

Another three birds were nursed back to health.

A Perth Zoo spokeswoman said the birds had presented to vets with paralysis of limbs and sometimes wings.

“Often the cockatoos do have injuries, including paralysis, because they have been hit by a car or shot,” she said.

“But the vets became suspicious when they found no broken bones.”

The spokeswoman said testing had indicated the birds were suffering from organophosphate poisoning, with one dead by the time it arrived at the zoo and others dying while in care or having to be put down.

She said the number of birds presenting with poisoning symptoms spiked in March.

“We haven’t seen a run of birds with these symptoms before,” she said.

“It is a concern because Carnaby’s blackcockatoos are endangered.” A Department of Environment and Conservation (DEC) spokeswoman said officers were investigating the deaths.

“There is insufficient information at this stage to determine whether the birds have been inadvertently or deliberately poisoned, however DEC is investigating to see if it can pinpoint the source,” she said.

Bentley resident Michelle Denise helped save one of the birds, which she found suffering from poisoning among pine trees in Technology Park.

She said she noticed something was wrong with the juvenile bird when it was struggling to move on the ground.

“It wasn’t moving anywhere and was trying to move forward but was falling on its beak,” she said.

“I knew something was wrong because he should have flown off.”

Mrs Denise alerted staff at Polytechnic West veterinary school, who rescued the bird and transported it to Perth Zoo, where it was nursed back to health.

The Perth Zoo spokeswoman said anyone who finds a sick cockatoo should take it to the zoo immediately for specialist care.