Arsenic May Be Killing Canberra Birds

by Sherry Morse

The currawongs and magpies who have lived at the Parliament House grounds in Canberra for years have almost all disappeared - and an insecticide is the prime suspect.

Meg Lees, an independent senator, requested an investigation into the bird deaths after fourteen dead currawongs were found in the last week in October.

It is possible that Cislin 10, an insecticide used by the Parliament House maintenance staff to control an infestation of Bogong moths, may be to blame.

Senate President Paul Calvert said an investigation into the bird deaths will be launched as "the coincidence of the spraying and the increase in bird deaths suggests there might be a link."

Cislin 10 is an organic poison used in dilution which should not normally have an effect on birds like the magpies and currawongs. In the past, Cislin 10 has been used on Parliament House grounds with no ill effect on the resident birds.

However, high levels of arsenic have been found in some Australian Alps Bogong moths, so if the birds have been eating the moths they could be getting poisoned that way.

In 2000, after heavy rains washed the moths' bodies out of the caves in the Snowy Mountains where they spend the summer, the accumulated arsenic in the moths killed all the vegetation outside the caves. Each moth was found to contain a small amount of arsenic in its system which has the potential to harm any animals or birds that eat the moths.

"Virtually everything eats them," said Dr Ken Green, wildlife ecologist with the New South Wales National Parks and Wildlife Service.

"It is difficult to estimate how many moths any given animal would have to eat for toxic effects to take place," Dr. Green said.

Animals vary extensively in the proportion of their diet the bogongs occupy and in the way they digest toxins, he said.

As part of the investigation, Bogong moths at Parliament House will be sent for testing to see if they contain arsenic, and any more dead birds that are found will be sent for testing to determine what caused their deaths.

© 2003 Animal News Center, Inc.