BOISE, Idaho — A large shorebird that nests in grasslands and uses its extra-long bill to pluck crustaceans from mudflats and wolf spiders from animal burrows will be the subject of an intense study this summer in three states.
The long-billed curlew is of particular interest to researchers because its downward curving bill allows it to live in a range of habitats, including cattle-grazed pastures, but populations appear to be flagging.
“They’re generalists,” said scientist Jay Carlisle of the Intermountain Bird Observatory at Boise State University, noting that the curlews also use native grass areas, mudflats and estuaries. “That would suggest flexibility. If there is decline, what does that mean with how we’re impacting them?”
This spring researchers in Idaho, Montana and Wyoming plan to put satellite transmitters on 19 of the ground nesting birds in hopes of getting a better understanding of the challenges they face. That’s more than triple the number of birds currently being tracked. The curlews can be up to several feet long, weigh several pounds and have bills longer than 8 inches.
Scientists say the birds face challenges on breeding grounds as well as on wintering areas in central California. Some birds also winter in Mexico.
One of the largest known breeding populations of the birds in the West was in southwest Idaho at the Long-billed Curlew Habitat Area of Critical Environmental Concern, a 45,000-acre area of mostly U.S. Bureau of Land Management land between Parma and Emmett.
About 2,000 curlews used the area in the 1970s. Current estimates put the number at less than 200.
“We’re talking about a 90 percent loss over a 30-year period, and we’ve continued to see a drop in the last six years,” Carlisle said.
There is no hunting season for curlews, which are protected under the Migratory Bird Treaty Act. But two birds with satellite transmitters have been shot in the area, and researchers have found five others also killed by gunfire.
Another problem, said Matt McCoy of the BLM, is off-road vehicle riders that create unauthorized trails through the grasslands.
“The unfortunate part is we haven’t done any public outreach or signage,” McCoy said. “This year we’re making a very concentrated effort.”
He said the agency plans to close some of the illegal off-road paths and is putting up signs alerting visitors to the significance of the area. The agency recently published a brochure with more detailed information.
The decline of curlews in southwest Idaho led scientists to wonder about other breeding populations, Carlisle said.
That has led to studies at The Nature Conservancy’s Flat Ranch Preserve in eastern Idaho and the Big Creek Ranch in the Pahsimeori Valley in central Idaho. In Montana, researchers plan to study curlews at a private ranch south of Missoula.
In Wyoming, researchers are working at The Nature Conservancy’s Heart Mountain Ranch Preserve near Cody, the National Elk Refuge near Jackson Hole, a site in Grand Teton National Park, and another near the town of Daniel.
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