he federal government has dropped its effort to shut down a Prince George's County garbage dump after finding that the dump has not attracted enough seagulls to endanger more delicate birds in an adjacent wildlife research center.

However, federal authorities said they will continue to keep a close watch on the Bevard landfill to be sure that it does not draw scavenger birds - often carriers of disease - in numbers that would threaten the whooping cranes and bald eagles in the nearby Patuxent Wildlife Research Center.

In the first action taken by a new environmental unit in the U.S. attorney's office in Baltimore, the federal government asked on May 30 for a court order closing down the landfill, which had opened on the site northwest of Bowie only three weeks earlier.

In July, according to assistant U.S. Attorney Edward M. Norton Jr., the government won an order requiring the landfill to tighten controls on sediment and surface water runoff from the landfill site.

Norton said the order was sought because the runoff was contaminating ponds where research was conducted at the Patuxent center.

The 4200-acre center is the principal U.S. Fish and Wildlife Service facility for wildlife research in the eastern United States, and according to the original suit, some of its programs are "very sensitive to external disturbance."

The center is supported by an annual budget of $8 million and shelters several species of endangered birds and mammals.

The landfill is operated by a private concern under contract with the Maryland-National Capital Park and Planning Commission. County officials have described it as crucial to the county's ability to dispose of refuse.

In addition to the runoff problem, the other major concern posed by the landfill was seagulls and birds sharing gull's appetite for refuse, Norton said.

He said it was believed that these birds would increase the risk of transmission of bird diseases to the rarer fowl at Patuxent.

However, he said last night, a review showed that "at this time there have not been large numbers of birds at the landfill." As a result, he said, the government dropped the suit Friday "to afford the landfill the opportunity to demonstrate over a period that it won't attract brids in such numbers that would present a threat to the center"

Norton added that seagulls generally flock to landfills in greatest numbers in colder weather, when other food sources diminish.

The government lawyer said the suit could be reinstituted if it appears necessary.