Testing underway after mass bird death in country WA

A wildlife carer in Western Australia's Wheatbelt says 78 birds have been found dead or dying in a local town, with the cause now under investigation.

Shannyn Bean, a wildlife carer in Coorow, around 260km north of Perth, said locals began finding the dead and dying birds on the town's oval and school grounds on Wednesday.

She said the birds, largely corellas and galahs, appeared normal when taken into care, only to rapidly deteriorate.

Ms Bean said she and her organisation, Bluebush Wildlife Rescue, had contacted WA's Department of Primary Industried and Regional Development (DPIRD) when the first dead birds were spotted.

"After coming into care they are dying, and we are unsure why," she said.

"They're on the ground, they're reluctant to move, they're sluggish, and they are easily picked up which is concerning because you should never be able to put your hands on a dead bird."

Corellas are classified as an invasive pest in WA and subject to organised culls.

Even so, Ms Bean said determining the cause of deaths was important to ensure vulnerable local species like the Carnaby's black cockatoo were not under threat.

"People have been speculating that it could be due to poisons. Because of the recent mouse plague, poisons have been utilised," she said.

"But we can't confirm that is the cause of what is going on."

Mouse baits on paddocks

The mystery bird deaths come as the region battles its worst mouse plague in living memory, forcing farmers to spread baits in a bid to reduce mice numbers.

Paddock-approved baits are grains of wheat containing zinc phosphide.

Last month, the pesticides regulator approved the use of double-strength baits on severely impacted farms.

Baiting is governed by strict guidelines, including rules about how and where baits can be spread.

The legal rate for application of zinc phosphide grains in paddocks is three grains per square metre.

CSIRO testing has so far found there is a low risk to birds from zinc phosphide baits if they are spread at the legal rate.

In March, the regulator banned the use of second generation anti-coagulant rodenticides for anyone other than licensed pest controllers, due to their impact on other wildlife.

Reportable disease concern

Ms Bean said all of the birds who had died were grain-eating creatures.

After her wildlife rescue group requested a full toxicology report on one of the birds, DPIRD told the ABC it would grant this request.

"They are going to test for Newcastle Disease and Avian Influenza first and foremost,"

Ms Bean said.

"The cause of these deaths may be due to a number of factors and DPIRD will be undertaking routine testing to exclude reportable diseases," a department spokesperson said.

"On this occasion, DPIRD will work the landholder to ensure samples are sent for relevant toxicology and cover the costs of this testing.

"Members of the public are reminded not to touch dead birds and to keep pets away."

Sightings of five or more sick or dead birds should be reported to DPIRD's Emergency Animal Disease Hotline (1800 675 888), while other reports of sick, orphaned or injured wildlife should be called through to the Wildcare Helpline (9474 9055).