Pesticides Kill Up To 20,000 Birds

North American hawks that summer in eastern Oregon died by the thousands in Argentina last winter, the victims of pesticides used to kill the birds’ main meal, grasshoppers.

Researchers found the carcasses of 5,000 Swainson’s hawks killed by pesticides on the agricultural plains of Argentina. Brian Woodbridge, a U.S. Forest Service hawk expert, estimates as many as 20,000 of the hawks died at their wintering grounds in one of the largest hawk kills documented.

From 1 percent to 5 percent of the entire population of Swainson’s hawks may have died, said Mike Hooper of Clemson University’s Institute of Wildlife and Environmental Toxicology.

Tests at Clemson University and interviews with Argentine farmers point to several highly toxic pesticides, including monocrotophos, an insecticide no longer used in the United States and Canada.

That pesticide has been linked to bird kills for 20 years.

Argentine farmers used it to control grasshoppers even though Argentina prohibits using the pesticide that way.

Maria Elena Zaccagnini, a biologist in Argentina, said her country is working with biologists from other nations and hopes to have a solution before the coming season.