Pesticide Poisonings Cited by Toxicologists : ‘Lawn-Care Syndrome’ Blamed for Bird Deaths

When songbirds die of pesticide poisoning, wildlife specialists such as Diana Conger chalk it up to what they regard as a growing phenomenon. They call it “lawn-care syndrome.”

Conger, a volunteer licensed by the U.S. Fish and Wildlife Service to treat sick and injured wild birds at her Bethesda, Md. home, said she has seen about a dozen birds that she suspects suffered from poisoning in recent months from Bethesda and Potomac, Md., and northwest Washington. It is the same every spring, she said.

The birds show the classic signs of pesticide ingestion--”shivering, excessive salivation, grand mal seizures, wild flapping, sometimes screaming,” Conger said. Most cannot be saved.

Wildlife toxicologists say that, although chemical-related deaths of bald eagles and other birds of prey have long been documented, songbird poisoning from lawn-care products is a little-studied environmental problem, one that has only begun to surface this decade.

Deaths Seen as Harbinger

“We are looking at the death of wildlife from pesticides as the harbinger of what’s being done to the environment,” said Edward Clark, director of the Wildlife Center of Virginia near Staunton.

Pesticide manufacturers and lawn-care companies say their products are safe when used as directed. Spokesmen for companies such as ChemLawn said that they are not hearing about the deaths of songbirds and that any such cases arise from excessive or careless application of chemicals.

Little systematic data are collected tying avian mortality to pesticides, in part because songbirds such as robins, blue jays and mockingbirds tend to die out of sight and then rapidly decompose, environmentalists said. Few states are equipped to determine pesticide levels in animals; toxicologists say the laboratory tests can cost $200 to $1,000 per bird.

But rehabilitators and researchers say the scattered bird kills they have been able to prove through testing reflect the growth of the lawn-care industry and the increased use by homeowners of pesticides to control insects and weeds.

More Toxic Chemicals

Although pesticides are used more widely on agricultural land than on lawns, the National Academy of Sciences has reported that homeowners tend to use up to 10 times more per acre of toxic chemicals.

“The homeowner figures they can’t sell it in the hardware store if it’s not completely safe,” said Edward Clark of the Wildlife Center of Virginia. “If it says, ‘Sprinkle on lightly,’ they figure, ‘Well, we’ll put on a heavier dose and get a more effective job.’ ”

Earthworms crawl out of the treated soil, trying to escape the poisons, “and robins snarf them up like candy,” Clark said.

The Chesapeake Wildlife Sanctuary near Bowie, in a report on what it described as a “tiny sample” of pesticide deaths, said last year that the Washington suburbs are becoming increasingly toxic to wildlife, particularly young birds and animals.

Autopsies on nine birds found in Maryland, conducted by Ward Stone, New York state’s wildlife pathologist, confirmed that they had died of pesticide poisoning.

The songbirds act as “miners’ canaries for us” in detecting when the buildup of chemicals may ultimately threaten humans, said Stone, a national expert on the subject.

Deaths of Waterfowl

Stone has documented more pesticide-related bird deaths than any other scientist in the country, starting with large flocks of waterfowl on golf courses and other public land on Long Island in the early 1970s. He said he sends his reports to chemical companies, including ChemLawn, which was sued by New York state last year for allegedly misstating the safety of its pesticides in its advertising.

The New York state attorney general said ChemLawn was falsely implying that federal registration of its chemicals is equivalent to an endorsement of safety certification by the Environmental Protection Agency. ChemLawn has filed a lawsuit asking a state court to uphold its procedures.

Without lab tests, unproved speculation linking bird mortality to pesticides comes from “amateur scientists practicing forensic toxicology,” said Roger Yeary, a veterinarian, who is a staff toxicologist at ChemLawn headquarters in Columbus, Ohio. “You have to recognize that there are about 3 1/2 million birds that die every year running into windows,” Yeary said, citing a 10-year-old Fish and Wildlife Service report.

“If there are bird kills, they are going to be by and large from misuse” of lawn-care products, he said. “There’s little doubt about that. There may be misapplication or pooling of some product, or the homeowner may put it around a bird feeder.”

Potential for Harm

Manufacturers concede, in part in their instructions to consumers, that with misuse there is potential for harm to birds and other wildlife, though Stone contends that such warnings are inadequate. “You can follow the label directions to a T and it still can result in killing birds,” he said.

Although a few lawn-care companies here offer organic alternatives to chemical pest control, the Environmental Protection Agency suggests changing lawn-care techniques to avoid overuse of pesticides. Letting grass grow longer, fertilizing only in the fall, mowing only in the evening, keeping the lawn mower blade sharp and aerating lawns with small holes are recommended by Philip Catron, president of the NaturaLawn company in Takoma Park, Md.

Another possible alternative, said Elwood Hill, a research toxicologist at the Patuxent Wildlife Research Center in Laurel, Md. is “to live with weeds. A weed is just a judgment call.”

Chemicals that have been federally approved for use on lawns include organophosphates that were substituted for DDT after it was banned for sale in 1972; chlorinated hydrocarbons such as DDT that have been restricted but still linger in the environment and in private stockpiles, and carbamate insecticides, toxicologist Stone noted in one of his many published papers on bird poisonings.

Toxic Levels Established

“Ten years ago, we legitimately did not think these chemicals were going to be a problem,” said Patuxent’s Hill, whose work has established toxic pesticide levels for birds.

The newer chemicals do not linger in the environment as long as DDT but have proved far more immediately toxic to birds.

One example is diazinon, a chemical that the EPA has tried to ban for use on golf courses and turf farms that attract waterfowl. Largely through Stone’s studies, diazinon has been linked with mass deaths of birds in New York state and elsewhere.