The federal government is considering easing restrictions on a baited cyanide device used to kill coyotes on western grazing lands, contending that the device is "less costly and more effective" than shooting the animals or using other poisons.

The effort, which has drawn heated protests from environmental groups, comes less than a year after the Environmental Protection Agency lifted a 13-year ban on Compound 1080, another poison long favored by western livestock producers.

The device, called an M-44, shoots a sodium cyanide capsule into the face of any animal that tugs or paws at it. The spring-loaded device has been used since 1975, but has been stringently regulated because of its threat to animals other than the predators it is intended to destroy.

Environmentalists contend that changes being considered by the EPA at the request of the Interior Department would eliminate or weaken many rules, including requirements that ranchers know exactly how many M-44s they have set and where each was placed.

"This is wildly unwise," said William A. Butler of the National Audubon Society, who told the EPA in written comments that "even the Easter Bunny forgets where he hides all the eggs, and his eggs don't explode, shooting cyanide into the face of those subsequently discovering them."

Agriculture Department officials contend that the changes would not increase the use of M-44s and that ranchers would still have "general knowledge" of where the lethal traps were set.

USDA took over the case for the M-44s last year after Congress transferred responsibility for predator control from Interior's Fish and Wildlife Service to USDA's Animal Plant and Health Inspection Service (APHIS).

"Nobody I know has ever had any trouble going back to the place" where the devices are set, said APHIS official Dick Winters. "It's a natural ability these trappers get through experience."

EPA's decision last July to put Compound 1080 back on the market was made partly on the basis of testimony that the M-44 was unreliable and ineffective. According to Dale Wade, a predator control expert from Texas A&M University, the device malfunctions easily, its trigger wire wears out and it is sometimes fouled by sand and grit.

"When ranchers wanted Compound 1080 they said the M-44 didn't work," the National Audubon Society and Environmental Defense Fund told the EPA. "Now that they have Compound 1080, they want M-44s without restrictions."

A spokesman for the National Cattlemen's Association acknowledged that there was "a pretty good effort to discredit other efforts" in the quest for Compound 1080, but that ranchers have "always viewed the M-44 as a means of providing safe and effective predator control."

The Fish and Wildlife Service also wants some restrictions on M-44s eased as a way of protecting endangered species. In a separate request to the EPA, the Interior agency said it wanted permanent permission to use the cyanide traps in wildlife refuges to kill coyotes that prey on eggs and young birds.

Service spokesman Megan Durham said 14 whooping crane eggs and as many as 50 flightless young whooping cranes were lost at the Gray's Lake Wildlife Refuge in Idaho in the last decade, and coyotes were preying on the endangered Mississippi sandhill crane as well.

The M-44 has been blamed for killing some endangered species, however, including a California condor in 1983, a grizzly bear in the late 1970s and a sandhill crane last November. "These incidents prove that the M-44 is non-selective and is dangerous to the species which the Interior Department seeks to protect," said Defenders of Wildlife, which told the EPA that aerial shooting of predators would be more effective and cheaper.

Fish and Wildlife Service official Larry Kline said the agency is using the M-44 under a permit that must be renewed annually, and "that causes trouble as far as delays and administrative problems." The agency applied for the permanent rule change at EPA's suggestion, he said.

Kline said his agency's request was "only loosely related" to the much broader changes supported by the Agriculture Department, which have drawn the heaviest fire from environmental groups.

"Having been successful with Compound 1080, they think they might as well loosen up on the M-44 while the going is good," said Butler. "The next step will be to hand them out like Roman candles on the Fourth of July."