The long-billed curlew is the nation’s largest shorebird but its fate may lie in the grasslands of southern Idaho and the Great Basin. See more photos
Video here Researchers from the Idaho Bird Observatory at Boise State University are trying to determine why numbers of nesting pairs of the birds has dropped so precipitously since they were first counted on the rangeland between Emmett and the Treasure Valley in the 1970s. The birds spend the winter from the Gulf of Mexico, across Mexico and to California, so scientists need to know where Idaho’s birds go to understand their life and threats.
A caravan of cars and trucks drove slowly up a dirt road through rolling hills of public land north of Middleton. An observer might have thought they were watching a game drive through the veldt of Zambia May 9.
The biologists and volunteers were heading to a nest that technician Ben Wright had found after hours of searching. They drove past grazing cattle, men with guns shooting ground squirrels and wide, bare trails pioneered by trucks, all-terrain-vehicles and motorcycles. Parasailers soared in the windswept tall grass.
The sagebrush is gone or limited to small patches, likely from decades-old burning to improve the productivity for grazing. But, perhaps because of the burning, the native bunchgrass is thick and healthy.
“A lot of people see this as a biological wasteland,” said Deniz Aygen, a bird biologist and coordinator of the Department of Idaho Fish and Game Department’s Watchable Wildlife program. “But you see with these nuggets of biological diversity how valuable it is.”
Once they get a few hundred yards from the nest the drivers park the automobiles and Research Biologist Jay Carlisle and Wright get out a long net, which they carry around the back of the nest. The male flies off, making a sharp twill sound “wid, wid, wid.” But the female hunkers down on her eggs, even when a rancher drives past on the road less than 10 feet away.
Carlisle and Wright carry the net directly over her, catching her in it. Carlisle carefully grabs her, making sure he leaves her legs loose as curlew handling expert Fletcher Smith from the Center for Conservation Biology in Virginia has instructed.
Smith was brought in to teach the team how to place a satellite transmitter on the back of the curlew. The small-solar-powered transmitter, which only operates intermittently through the day, will show scientists where the birds go year-round.
“We can sit and watch where she goes on our smartphone,” Carlisle said.
The temperatures in the low 80s are just right to leave the four eggs for the 30 minutes it takes to attach the transmitter.
Carlisle carries the bird to the air-conditioned cab of a pickup where he and Smith place the transmitter on its back. After its on and transmitting, and they are sure she is no worse for wear, research biologist Jessica Pollack releases the gray and brown bird, which returns to the nest after a short flight.
The nest is in an Area of Environmental Concern, designated by the Bureau of Land Management in 1992. That means the agency seeks to protect the curlew and works with the rancher who owns the cattle in the area.
Still, the number of nesting birds has dropped to 150-300 in recent counts over the last four years compared with 1,000 in the area in 1977-1979, Carlyle said. Reproductive success is very low, Carlisle said, a 70 to 85 percent failure rate.
Grazing patterns haven’t changed but the area gets far more recreational use today than in the 1970s as the population of the Treasure Valley has grown. The ground squirrel population also appears to be higher, Carlisle said, which may have attracted more ravens and other predators.
One possibility, Carlisle says as he drives, is that the habitat structure has changed. Curlews like short grass near their nest so they can watch as any predators approach.
“Some of the areas have become tall and weedy,” Carlisle said.
Likely, the birds need a mosaic of tall and short grass so they and their chicks can hide after the hatch. The biologists have also found curlews shot and left by shooters.
But the birds live others places after they leave Idaho and it maybe changes in the habitat along shorelines and wetlands elsewhere that account for the population drop.
“Maybe the issue is on their wintering ground,” Carlisle said.
They hope the curlew survives the summer and the trip to Mexico or California or wherever it ends up.
“I won’t breathe a sigh of relief for nine months when we see where they went,” said Smith, the handler.