Montana's greater sage grouse population has fallen more than 40% over the past three years, mirroring recent declines across the U.S. West for the wide-ranging bird species that federal officials rejected for protections in 2015.
State wildlife officials estimate there were about 44,000 ground-dwelling sage grouse in Montana this spring. The figure is included in a report to be delivered to state lawmakers later this month.
Sage grouse once numbered in the millions but have seen their range that stretches across portions of 11 states diminished by oil and gas drilling, wildfires, grazing and other pressures.
Grouse numbers also continued to drop in 2019 in Oregon, Idaho , Nevada and Wyoming. Weather can affect populations from year to year, and wildlife officials say those short-term cycles are most directly responsible for the recent declines.
Montana's drop from almost 78,000 grouse in 2016 was traced to an extreme drought in eastern parts of the state in 2017 that had prolonged impacts, said Catherine Wightman with Montana Fish, Wildlife and Parks.
The decline coincides with increased efforts to conserve grouse habitat, including by working with private landowners to adopt grazing and other practices that are more beneficial to the bird.
"That doesn't mean those plans are not working and doing the right thing," said Wightman. "We're seeing this overall decline. The analysis shows overall the (population) peaks are getting a little lower and the valleys are getting a little lower. What we'd like to do is stabilize our numbers."
Wyoming's population drop was measured by counting the number of male birds strutting on grouse breeding grounds known as leks, said Sara DiRienzo with Wyoming Game and Fish. The number of birds per lek has dropped about 20 percent since 2018 and more than 40 percent since 2016, according to agency figures.
This year's numbers are still above the low levels reached in 2013, DiRienzo said, and likely reflect dry conditions and extreme winter weather that caused many chicks to die.
Wyoming does not have an overall population estimate.
Brian Rutledge with the National Audubon Society said the population drops should not be written off just because they are cyclical, since ongoing habitat loss makes it harder for the bird's numbers to rebound each time they drop.
"We're not in a position to say this is OK. We have too many things working against us," he said.
In Oregon, bird numbers this year reached their lowest number since reliable estimates have been recorded beginning in 1996, said sage grouse conservation coordinator Lee Foster with the Oregon Department of Fish and Wildlife. The state counted approximately 14,000 grouse, less than half the state's target of 30,000 birds.
"I'm very hopeful we're at the bottom this year," Foster said. "There is cause for concern even if the trend fits within what we would expect with the population cycle."
Grouse numbers in Idaho have dropped more than 50 percent since 2015. Nevada reported an 8 percent decline this year in lek counts of male birds.
The bird's population also was down in Utah, with the 2019 lek count marking a 61% decline from 2015, according to state wildlife officials. Part of that low number was attributed to a snowpack that lingered longer than usual, preventing people from getting to some of the areas they normally count, said Blair Stringham of the Utah Division of Wildlife Resources.
The 2015 decision not to protect sage grouse under the Endangered Species Act came after state and federal officials crafted sweeping conservation plans for the birds across their range.
Under Republican President Donald Trump, the Interior Department has relaxed restrictions on mining and drilling that were included in the original plans adopted under his Democratic predecessor, Barack Obama. Impacts from those changes are expected to be long-term and not reflected in the latest population numbers.