Tuesday, June 02, 2009

Birds Dying in Western Australia

Over the weekend, there was a rash of bird deaths in Western Australia, at a landfill site south of Perth. The description of the symptoms sounds horrible:
DEC Pollution Response Unit environmental hazards manager Ken Raine said birds were seen frothing at the mouth and staggering around at the tip yesterday before scores of dead birds were discovered within a kilometre radius of the landfill site.

By today the body count had climbed to more than 200 with ibis, silver gulls, pacific black ducks, a raven and a pelican among the dead....

Some seriously ill birds have also been found among the bodies and are being monitored in a bid to determine the cause of the mass deaths.
The DEC's investigators are now blaming the deaths on a pesticide, Fenthion, but have not determined who dumped it at the landfill or why.
DEC pollution response manager Ken Raine said samples had been taken from waterways to check for contamination and the rubbish tip had been covered with sand while investigations were continuing.

Fenthion is a broad-spectrum organophosphorus insecticide used to control horticultural pests such as fruit fly and aphids as well as mosquitoes and other insects.

It is an active ingredient in a number of products sold at hardware stores, including fly baits and fruit fly sprays. It was not known yesterday how much poison would have been needed to cause so many deaths.

A DEC spokeswoman said if the birds were deliberately poisoned it was an offence under the Wildlife Conservation Act, with fines of up to $4000 for each bird species affected. Illegal dumping of pesticides was covered by the Environmental Protection Act.
A year ago, about 200 gulls died near the same location from an unknown cause. In 2007, lead poisoning killed about 4,000 birds in Esperance on Australia's southern coast.

Fenthion is currently legal in Australia but under review by the Australian Pesticides and Veterinary Medicines Authority. Australia's Northern Territory advises disposing Fenthion away from waterways, which seems not to have been done in this case. Fenthion has been found to be highly toxic to several native Australian bird species.

For those who are curious, Fenthion has been used in the United States to control mosquitos, especially in the aftermath of initial West Nile Virus outbreaks, and in dog shampoos. While it is primarily an insecticide, it is also highly toxic to birds and sometimes used as an avicide (the "Rid-A-Bird perch"). Even when used as an insecticide, its application can result in bird deaths; the American Bird Conservancy lists several incidents of mass bird killings. Due to concerns over its toxicity to humans, it was withdrawn from the U.S. market in 2004 and the EPA canceled its registration.