A key defendant in a major wildlife-smuggling case told federal investigators that members of the Saudi royal family were prime customers for illegally exported falcons and other protected birds of prey, according to documents filed yesterday in federal court.

The defendant, Glen Luckman, pleaded guilty in U.S. District Court in Great Falls, Mont., to four counts of a federal indictment charging him with unlawfully trapping and exporting wild gyrfalcons, peregrine falcons and other raptors.

Luckman was one of nearly 40 people arrested in 14 states in June after a three-year undercover investigation into what the government believes is a major international black market in the birds. The Justice Department believes that hundreds of birds are being trapped and sold illegally to wealthy falconers in the Middle East and Europe, where hunting with birds is still known as "the sport of kings."

In a statement that accompanied Luckman's plea, federal prosecutors said that, in meetings with a government informant, Luckman and other alleged falcon-traffickers had discussed "selling falcons to the Saudi Arabian royal family," including the crown prince and the defense minister.

According to the statement, Luckman told U.S. Fish and Wildlife Service informer Jeff McPartlin that highly prized gyrfalcons would sell for up to $30,000 apiece during the Arabs' autumn buying season and that a white female gyrfalcon might bring as much as $100,000.

Another defendant later told McPartlin "that he had been in contact with an Arab who provided falcons to the crown prince of Saudi Arabia," the statement said.

The statement does not detail any actual sales to members of the Saudi royal family or to any other Middle East customers, but Justice Department officials yesterday called Luckman's plea the "most significant" action to date in their efforts to end the black market for raptors.

Don Carr, chief of the department's Wildlife and Marine Resources Section, said the Justice Department is "not drawing firm and irrevocable conclusions" but intends to "turn over every stone on the trail to the Middle East."

"This information about the so-called Saudi connection dovetails with other aspects of our investigation," Carr said. "The highest transaction values that we've heard of by far are in Saudi Arabia."

Last August, when another of the alleged smugglers entered a guilty plea, a Fish and Wildlife agent testified that the Saudi Arabian Embassy in Washington had helped smuggle birds out of the country.

The agent, Don Schmidt, said the embassy provided a limousine to take six gyrfalcons to New York, where the birds apparently were given first-class tickets on Saudi Arabian Airlines, destination unknown.

The Saudi Arabian Embassy did not respond to a request for comment yesterday. In August, an embassy attorney was quoted in The New York Times as calling the allegations "bird feathers."

Carr said the State Department is aware of the Justice Department's investigation, but "whether and what law-enforcement route ought to be followed is wide open to debate. Obviously, there are diplomatic-immunity implications."

Meanwhile, he said, Justice officials are about halfway through their list of defendants, handling the cases of the "least culpable" first.

"So we're just at the beginning of our work," he said. "This is not to be taken as the totality but the introduction. The illegal market is even bigger than we thought it was."