BILLINGS, Mont. — America’s golden eagles face a rising threat from a black market for their feathers used in Native American ceremonies, according to wildlife officials, researchers and tribal members.

The government’s response has been two-pronged: A crackdown on rings illegally trafficking dead eagles coupled with a longstanding program that lawfully distributes eagle feathers and parts to tribal members.

But that program has a yearslong backlog, partially because of avian flu, and officials said illegal killings appear to be worsening, with young golden eagles in particular targeted because of high value placed on their white and black wing feathers. Golden eagles, which are federally protected but not considered endangered, already faced pressure — from poisonings, climate change and wind turbines.

An investigation centered on a Montana Indian reservation recently landed its first conviction: A Washington state man accused with others of killing thousands of birds, including at least 118 bald and golden eagles, and selling their parts in the United States and abroad.

He was sentenced last week to nearly four years in prison and ordered to pay up to $777,250 in restitution in a prosecution that has offered a rare glimpse into the black market.

Another investigation involving undercover agents recovered 150 golden and bald eagles over the past decade across several states, with 35 defendants charged and 31 sentenced for wildlife violations, according to court records and federal officials.

Perry Lilley, a member of the Nakota Tribe in northern Montana, attends numerous Native American ceremonies a year and says he has been solicited to buy eagle feathers. He said illegal shootings were “absolutely wrong” but sympathized with tribal members who don’t want to wait years for eagle parts.

Eagle feathers are woven into Native American culture. Beyond Native American ceremony regalia, they’re presented to high school graduates, used in marriage ceremonies and buried with the dead.

A government repository in Colorado that provides dead eagles and their parts for free to tribal members keeps up with orders for individual feathers, such as for graduates. Yet it’s unable to meet demand for eagle wings, tails and whole birds, even as ceremonies become more elaborate and competitive.

That’s left an opening for criminals to exploit Native Americans who are trying to keep traditions alive.

“The amount of money that you can win in powwows has increased a lot in the last 10 years, which has increased some of the demand,” said Ed Grace, chief of law enforcement for the U.S. Fish and Wildlife Service. “If the price of feathers goes up, people ... become opportunistic and see that you can make a lot of money in a relatively short period of time poaching eagles to provide for the feather trade.”

In the Montana poaching case, the defendant and accomplices were accused of killing about 3,600 birds — including golden and bald eagles — during what one defendant called a “killing spree.” Prosecutors say the killings began in 2009 and continued until 2021 on the Flathead Reservation, home of the Confederated Salish and Kootenai tribes.