An extensive investigation into the deaths of hundreds off birds of the North Queensland coast has failed to identify a cause.
- Disease and environmental factors weren’t determined as cause of death
- No contaminants were found in water samples from the Marina
- Investigations into other bird deaths in the World Heritage area are continuing
Scores of black noddies were found in the Mackay Marina in August and September, with dead and ill birds also found around Bushy Island and other known roosting sites.
Initial investigations suggested chemical pollution was to blame, with a light, greasy film found on the feathers of the birds.
But that’s now been ruled out.
A helicopter survey of islands off the Mackay coast in the days after the birds were discovered found no sign of an obvious pollution event or slick.
No answers despite extensive testing
The Department of Environment and Science said in a statement water samples taken from the Mackay Marina found no contaminants or any unusual water quality results.
“Swab samples taken from feathers of deceased birds found in the marina were screened for organic contaminants such as pesticides, herbicides and hydrocarbons. No organic contaminants were detected and there was no direct evidence of death due to chemical exposure.”
As well as external factors, vets also conducted tests on dead birds from Bushy Island to see if disease was the reason for the deaths.
Vets tested for a variety of diseases, including Influenza A, Botulism poisoning and Kunjin Virus, which can cause severe neurological disease and death in several animal species.
All of the tests came back negative.
A case of poor health?
What the testing did reveal is that a number of the birds had a lack of food in their digestive systems.
Others were also found to have heart disease, lung disorders and liver damage, but the cause of these conditions wasn’t able to be determined.
A multi-agency investigation is continuing to investigate similar bird deaths in waters in the Great Barrier Reef World Heritage Area.