Greater sage grouse numbers in the West have grown by nearly two-thirds since 2013, marking what could be a significant rebound to the bird’s previous several years of decline, according to scientists in Western states.
Western state biologists said they spotted 80,284 male sage grouse across the West in 2015, a 40 percent jump over the 57,399 that were spotted in 2014 and 63 percent over the 49,397 that were spotted in 2013, according to yet-to-be-published research compiled by the Western Association of Fish and Wildlife Agencies and shared with Greenwire.
Sage grouse experts caution against drawing conclusions from the two-year spike, noting that sage grouse populations appear to fluctuate on roughly decadelong cycles and are influenced in the short term by precipitation.
Yet the new data from state fish and game agencies is undeniably good news for Western states that are fighting to keep the bird from being listed under the Endangered Species Act. The WAFWA data are being sent to the Fish and Wildlife Service to inform its pending decision on whether grouse need ESA protection.
The recent population bump "was huge," said Tom Remington, a sage grouse coordinator at WAFWA who compiled the data and presented it last month at WAFWA’s summer meeting in Reno, Nev. Remington is a former director of the Colorado Division of Wildlife.
The research comes months after the release of a study by University of Idaho wildlife ecologist Edward Oz Garton and commissioned by the Pew Charitable Trusts that found the number of breeding male grouse fell by more than half Westwide between 2007 and 2013 (E&E Daily, April 24).
State wildlife officials said the report cherry-picked just the years of decline — 2007 marked a major peak in sage grouse populations, and 2013 could be a trough, they said. To identify long-term population trends, state officials recommended looking at how past peaks and troughs compared to the most recent peaks and troughs.
Estimating actual sage grouse populations is a tricky task given that they inhabit many millions of acres in 11 states. Scientists generally count only male grouse because they are easy to spot during their springtime mating dances. The relatively reclusive hens exhibit "cryptic" behavior, FWS said, and scientists do not know how many may be lurking in the brush.
Research suggests there are hundreds of thousands of total sage grouse on the landscape, a dramatic decline from the estimated millions that blackened Western skies in the early 20th century.
While the 2014 and 2015 data say little about long-term trends, they do suggest the sage grouse population pendulum is swinging back up. It could support an FWS conclusion that ESA protections are not warranted.
"Short term, virtually everyone saw a pretty dramatic uptick in birds," said San Stiver, a sage grouse coordinator for WAFWA.
Western state biologists also observed more active breeding grounds, known as leks, over the past two years, as well as a major uptick in male grouse per lek.
In 2006, biologists observed an average of more than 33 birds per lek, higher than at any time in decades. But that number fell each year until 2013, when there were fewer than 17 birds per lek. It rose to 18 in 2014 and 25 this spring.
While tallying the total number of males and the males per lek depends heavily on how hard scientists look for the birds, Remington said monitoring intensity has been relatively steady since around 2007.
The WAFWA data suggest that from the mid-1990s on, grouse populations have been pretty steady.
Much of the recent surge was driven by Wyoming, which is home to roughly 40 percent of the grouse’s rangewide population. The number of male birds counted in the Cowboy State was 18,238 in 2013, 20,050 in 2014 and 35,860 in 2015, according to state officials. Scientists checked about 1,600 leks, about 88 percent of the known occupied leks, in each of those years.
"Improved weather conditions are mostly responsible for the increased numbers," said Tom Christiansen, sage grouse coordinator at Wyoming’s Game and Fish Department.
In Wyoming, while sage-grouse have seen a "long-term decline" since the 1950s and ’60s, populations saw a "general leveling off since the mid-1990s," Christiansen said.
Montana and Colorado also registered major increases in birds, officials said.
The high count for males this spring in Colorado was 6,400, the highest ever counted in the Centennial State and about 50 percent above the previous year, said Kathy Griffin, statewide grouse coordinator at Colorado Parks and Wildlife. Griffin said northwest Colorado, home to about 4 percent of the nation’s sage grouse, had a mild winter and good moisture in the spring, similar to the conditions of the previous year. "Some momentum is building," she said.
In Montana, where the number of male grouse spotted at monitored leks hit an all-time low in 2014, numbers rebounded by 74 percent this year, said Catherine Wightman, habitat coordinator at Montana Fish, Wildlife and Parks.
Jack Connelly, a retired scientist for Idaho’s Fish and Game Department who co-authored the Garton report, said he has not seen the new WAFWA data but is skeptical whether sage grouse are in good shape.
"Look at what’s happened in terms of habitat [loss]," he said. "And look at the number of acres of sagebrush that have burned from wildfire as well as expansion of oil and gas on the eastern side of the range. Look at that and ask, ‘Does this make sense?’"
While recent population trends might factor into FWS’s listing determination, they are not one of the main criteria scientists may use under ESA. The 1973 law says a listing should be made on the basis of the "present or threatened" destruction of habitat and the adequacy of government regulations, among other threats.
The Fish and Wildlife Service in 2010 found sage grouse warranted listing because their habitat was increasingly degraded and fragmented by agricultural conversion, urbanization, roads, power lines, increasingly frequent wildfire, invasive plants, grazing and energy development, as well as insufficient regulations at agencies including the Bureau of Land Management, which oversees most of the grouse’s remaining habitat (Greenwire, March 5, 2010).
The extent to which stakeholders address those concerns will likely be central to FWS’s decision.
A Fish and Wildlife spokesman said it would be premature for FWS to comment on WAFWA’s data.
Some conservation groups intend to sue Fish and Wildlife if it declines to list the bird, arguing that the grouse’s sage steppe habitat remains vulnerable to oil and gas drilling, transmission lines, wind farms, mines, grazing, and other threats.
WildEarth Guardians last week released a report arguing that the BLM and Forest Service sage grouse protection plans reduced the size of priority habitat identified by Fish and Wildlife by about 20 million acres.
"Apparently, the federal agencies thought that they could sneak huge reductions in the acreage of priority habitats past the public by releasing all the plans at the same time," said Erik Molvar, a wildlife biologist with WildEarth. "But we caught them, and in plenty of time to alert the U.S. Fish and Wildlife Service to the dirty tricks land-use agencies are using to weaken grouse protections."
WildEarth said priority habitats in Nevada were slashed in the final BLM and Forest Service plans to roughly half of what was originally proposed. In Idaho and Utah, priority habitat was reduced by 3.8 million acres and 2 million acres, respectively, the group said.
"These drastic reductions in priority habitat radically increase the likelihood of extinction, and unless they’re corrected, they will only underscore the need for Endangered Species Act protections," Molvar said.