The U.S. Fish and Wildlife Service is investigating the possibility that a number of pigeon hawks were illegally imported from West Virginia by General Services Administration employes to rid a government building in Reston of its pigeon problem.

The investigation was sparked by a story in yesterday's Washington Post that a GSA assistant building manager at the Geological Survey Headquarters in Reston had imported a number of pigeon hawks, also known as merlins, to kill off a multitude of pigeons that infested the building's window ledges, leaving piles of potentially disease-infested droppings.

Special Agent Lloyd Lindvall of the Fish and Wildlife Service said the federal Migratory Bird Treaty Act prohibits taking birds of preycalled raptors -- from the wilds without a special permit. Permits, he said, can only be issued for the sport of falconry or for scientific research. The illegal trapping of these birds, Lindvall said, is a misdemeanor, carrying a possible penalty of six months in jail and a $500 fine.

Meanwhile, Roger Jones, of the Raptor Society of Metropolitan Washington, said he doubted that the birds the GSA building manager, Jerry Cuthbertson, described to a reporter were actually pigeon hawks. Jones said that after talking to Cuthbertson, he thinks the birds were more probably American kestrels, or sparrow hawks, which are smaller than pigeon hawks and normally eat mice and insects. This speculation was shared by Jim Ruos, of Fish and Wildlife's office of migratory bird management.

Jones further disputed the contention that the hawks were responsible for what Cuthbertson described as 50 pigeon kills. "Hawks aren't assassins, they kill to eat," he said. He said he also doubted that the hawks, once released, would stay "and live on a giant parking lot."

A GSA spokesman yesterday declined to comment on the hawks. Cuthbertson was unavailable for comment.