BOISE, Idaho (AP) — The long-billed curlew bird population is declining in southwestern Idaho because of poachers, researchers said.

One of the birds was poached in the Morley Nelson Snake River Birds of Prey National Conservation Area southwest of Boise on June 1, Boise State University researchers said.

Of the 16 birds fitted with transmitters, it's the seventh that has been killed by suspected poachers since 2013, the Idaho Statesman reported .

None of the 50 birds fitted with transmitters located in other parts of Idaho, Montana and Wyoming have been poached, according to researchers.

Curlews are migratory birds that reside in the Mountain West from March to June and spend their winters along the coasts of California and Mexico.

In southwest Idaho, their numbers are on a steep decline, with as much as a 90 percent decrease in some areas.

One of the main reasons for the decline is humans, researchers found.

"The proportions are alarming," said Jay Carlisle, associate research professor at Boise State University and research director of the Intermountain Bird Observatory.

Carlisle and his group focus their research on understanding the reproductive success of the curlews in different habitats as well as studying migratory patterns using lightweight satellite transmitters.

The curlew poached earlier this month was found by two of Carlisle's researchers, Stephanie Coates and Joni Clapsadle. The female bird had been shot through the wing and body, indicating that she was sitting on the ground when killed, close to her nest.

"This female was simply shot because she was there," a release from the Intermountain Bird Observatory said.

Recently, the birds appear to have been killed for no other reason than target practice — or worse, for no reason at all, Carlisle said.

The curlew is neither an endangered nor threatened species, but it is protected under the Migratory Bird Treaty Act. Killing a curlew is a federal crime — a misdemeanor punishable by up to a $15,000 fine and six months in jail.

Public outreach is the key to saving the species, Carlisle said. He stresses the importance of informing land managers and the community at large.

"In a decade, we may have a place named the Long-Billed Curlew Habitat Area of Critical Environmental Concern that doesn't have curlews anymore," he said. "How sad would that be?"