Wyoming should adopt a species-specific permit system for sage grouse hunting to better account for the fall take, a university professor recently told a state panel.
A greater sage grouse hunting regime that takes less than about 10% of the fall population has no added effect on the species’ annual natural mortality, the academic and a colleague also told the Wyoming Sage Grouse Implementation Team.
Members of the SGIT called for the hunting review after learning that hunters last season shot an estimated 7,600 greater sage grouse in Wyoming. Hunters still pursue greater sage grouse in seven of the 11 western states that are home to the chicken-sized bird, even though grouse numbers have declined alarmingly over recent decades. Hunting begins in two of Wyoming’s four areas Sept. 18.
“We didn’t find … any harvest effect on the Powder [River Basin] or the Wyoming Basin,” University of Wyoming professor Jeffrey Beck said of the two greater sage grouse management areas in Wyoming where hunting has been allowed. Along with Oregon State University professor Jonathan Dinkins, he summarized historic and ongoing research earlier this month.
The presentation brought a mixed reaction from SGIT members.
“Are we harming the population by hunting at the conservative levels [we have]?” SGIT chairman Bob Budd asked rhetorically after the meeting. “The answer was no.”
The presentation did not placate the director of the National Audubon Society’s Sagebrush Ecosystem Initiative and SGIT team member Brian Rutledge, however. Greater sage grouse, he said, should be more tightly managed — “much more like a trophy species than a game bird.”
How and whether hunting affects greater sage grouse, “we can’t make those conclusions with what [information] we have,” Rutledge told WyoFile.
A web of factors
Beck and Dinkins outlined the web of factors, including hunting, that impact greater sage grouse populations. The distinction between “additive” and “compensatory” mortality drives wild game hunting management, they said in their presentation which drew on hunting information dating back to the 1870s.
Compensatory mortality occurs when hunters kill a quantity of birds that’s roughly equal to a population’s “doomed surplus” — the number of animals that would die anyway from, for example, limited winter range. Additive mortality reduces a population beyond what would naturally occur, according to the framework proposed in 1936.
“Wildlife agencies tend to focus on hunting that surplus group of animals that [would be] dying for other reasons,” Beck told the panel. Based on that theory, researchers in 2000 first proposed no more than a 10% harvest of the estimated fall population of greater sage grouse, he said.
A 2010 study in Colorado and Utah that included information from banded birds supported that limit, finding no evidence that harvesting less than 11% of a fall population created additive mortality. Others believe in a 5% limit, Beck said, to ensure a conservative approach.
Hunting, however, should not occur in colonies that number fewer than 300 birds in the spring, researchers agree.
The hunting limit, whether 11%, 10% or 5% of a fall population, however, is complicated by the difficulty of estimating that fall number. The standard method of estimating grouse population trends centers on spring lek counts of males.
Most wildlife agencies compare year-to-year lek counts to discern trends. Most do not estimate, at least publicly, overall numbers for either the spring or the post-nesting period in the fall.
In recent decades as scientists began to see sage grouse numbers fall, however, they began to suggest different hunting-license strategies, the professors said. About 20 years ago, some researchers “started talking about sage grouse almost like a trophy species,” Beck said.
“If you’re going to pursue sage grouse, you need to consider it’s a really limited resource [because] not a lot of states have hunting seasons,” Beck said in describing the bird’s semi-elite status.
Wyoming’s license system might not reflect that value, however.
Wyoming game bird licenses allow holders to hunt greater sage grouse, blue grouse, ruffed grouse, chukar partridge, gray partridge, sharp-tailed grouse and pheasants. Seasons, daily bag limits and possession maximums vary by species and area. Hunting waterfowl and other migratory game birds like doves and snipe requires the same license, plus additional stamps and permits. A bird license costs from $9-$22, depending on residency and term.
The multi-species license isn’t conducive to the collection of accurate data about the annual toll on individual species, Dinkins told the panel. He recommended a system in which sage grouse hunters would purchase species-specific permits, thereby enabling wildlife managers to collect more and better information.
“The permit-only system, or something that could get close to that, would really be ideal for multiple reasons.” Dinkins said. Better data comes when “the more specific and targeted you get and the more requirements [you have] for your hunters.”
Advantages of a permit system
Game and Fish today gets some valuable information when hunters voluntarily put one wing from each sage grouse shot in a collection barrel. Game and Fish places barrels in various locations around the state.
By examining a wing, biologists can tell the harvested bird’s sex, whether it was a chick or an adult and, in the case of hens, even more. “You can tell if they had a nest or a successful brood,” Dinkins said.
Despite the value of that information, wing barrels have shortcomings. “You can only put up a wing barrel in so many places,” Dinkins said. Submission of wings remains incomplete for a variety of reasons.
A permit system could correct some of those deficiencies. By including envelopes with permits, for example, hunters could mail wings of harvested birds to Game and Fish resulting in more accurate data.
Implementing a more rigorous method of collecting wings comes with obvious costs, Dinkins said. “It’s way easier for Oregon, California, Utah [where] they’re not shooting as many birds,” he said.
Managers also could use a permit system to minimize the kind of excessive take that’s possible under today’s bag/possession-limit regulations. For example, in a seven-day season with a limit of two birds a day and four in possession, a single hunter could take more than a dozen birds.
“If you ate sage grouse all week, you could eat 14,” and still honor the letter of the law, Dinkins said.
Permits also could be used to limit the number of hunters in a specific area. The ability to better control hunter numbers and distribution could be advantageous to Wyoming as it faces more pressure from non-resident hunters when other states limit opportunities, Dinkins said.
A permit system would also help assure the public that game managers are closely monitoring the species. Given the fragile nature of the greater sage grouse population West-wide, optics could be increasingly important.
“There’s a public perception that [with] permit only hunting there’s more tight regulation,” Dinkins said. “We just get better data.”
More, better data
In their review of hunting reports, the two professors found that traditional surveys over-estimate hunter success for various reasons. Small sample sizes from mail surveys, for example, easily skew results, they said. Also, “you tend to have more successful hunters sending back [responses] to you,” Dinkins told the panel, and unsuccessful ones not responding.
Those answers have been wrongly extrapolated from traditional mail surveys to give a skewed result of harvests, he said.
Dinkins sought to correlate hunting closures in various parts of the West with population trends, but found little relationship.
But changes in regulations affect the number of birds shot each fall, according to the presentation. Pushing back the opening date of the season, limiting the number of grouse that can be taken in a day and limiting the number of grouse allowed in possession all can temper the annual toll.
But the fate of grouse appears most closely tied to the health and undisturbed nature of the bird’s habitat. Everything from drought, fire, invasive weeds, wild horses and encroaching juniper trees have an effect on the species, the two said. Human activities and developments such as oil and gas sites, residential subdivisions, transmission lines and wind turbines fragment habitat to the detriment of the bird.
Budd has faith in the Wyoming Game and Fish Department, he said, the agency that has a phalanx of biologists and that’s tasked with wildlife management and recommending hunting seasons and regulations. SGIT, a panel appointed by the governor, doesn’t have any of that authority or duty.
Rutledge wants more discussion about hunting, he said, challenging assertions that today’s take in Wyoming is compensatory.
“There’s no such thing in this species,” he said. “Anytime you’re in a decline, it’s hard to say simply what’s compensatory. We don’t have that data.”
“I’m looking for more input from Game and Fish,” he said. “I want to understand how they’re making their decisions. We haven’t completed that circle.”
A lot of agency biologists listened to the presentation to SGIT, Game and Fish Department’s sage grouse and sagebrush biologist Leslie Schreiber wrote in an email. She will assemble them soon to go over the presentation and discuss it and other sage grouse issues, she said.