Wildlife authorities investigating why thousands of birds fell from the sky over a town in remote southwestern Australia have ruled out infectious diseases, including bird flu, but are no closer to working out what killed them, a state official said Friday.
Around 5,000 birds have been found dead in Esperance, Western Australia, since mid-December, according to Nigel Higgs, spokesman for the state's Department of Environment and Conservation.
The birds were mostly nectar- and insect-eating species, although some seagulls have also been found, Higgs said in a telephone interview from his office in the Western Australia capital, Perth.
Pathologists at the Western Australia Department of Agriculture examined several of the carcasses, but have ruled out the virulent H5N1 bird flu virus and other infectious diseases.
"It does not appear to be an infectious disease," Higgs said. "It may be an environmental toxin. It may be an agricultural or industrial toxin. We just can't be specific."
Higgs said further tests were being done on the dead birds, and that it would be at least another week before pathologists have any more information on the mysterious deaths.
Meanwhile, the reports of dead birds were waning, the AP says.
"The numbers of reports of dead birds have slowed down a lot, which can mean a lot of the birds in the area have already perished," he said. "We're just hoping to - once we know the cause - determine the solution."
Michelle Crisp was one of the first residents of Esperance to report the dead birds, the AP says.
She told The Australian newspaper earlier this week that she normally had hundreds of birds on her property, but she and a neighbor had counted 80 dead birds in one day.
"It went to the point where we had nothing, not a bird," she was quoted as saying. "It was like a moonscape, just horrible."