Hunting, predation stir worry
Dave Watson loves riding snowmobiles and off-highway vehicles and is involved with clubs for both activities in Craig.
He believes proposed new Bureau of Land Management measures to protect the greater sage-grouse in northwest Colorado stand to impact those recreational activities “a bunch.”
That’s got him wondering: Why does Colorado Parks and Wildlife allow hunting of a bird that the Fish and Wildlife Service has declared a candidate species for being listed for protection under the Endangered Species Act, something the BLM is hoping it can help keep from occurring?
“(Hunting) has got to do some damage to the population of the sage-grouse,” he said during a recent BLM open house in Craig.
For that matter, Watson said, he never hears mention of the impact predators have on the bird.
“Maybe we need to think about controlling predators,” he said.
Others are raising similar concerns. Garfield County Commissioner John Martin this week also questioned allowing hunting of the sage-grouse and said the bird’s numbers rose during a predator-control study in the Pinedale, Wyo., area, and then plummeted after it ended.
“(It was) not because of man or industry or farming or anything else — it was predation,” he said.
David Ludlam, executive director of the West Slope Colorado Oil and Gas Association, said his industry hasn’t taken a position on hunting sage-grouse, and it’s not “top of mind” for them regarding the bird’s management. But he said allowing it sends “a mixed message that undermines everybody’s passion and energy toward doing whatever it takes to conserve the species, which we all agree is the right thing to do.” He said he wonders how much sense it makes to allow hunting when other measures to protect sage-grouse could force energy companies to leave tens of billions of dollars worth of natural gas and oil in the ground.
Colorado Parks and Wildlife officials are well aware of the questions surrounding hunting and predation as those two issues relate to sage-grouse management. But Brad Petch, senior terrestrial biologist for CPW’s Northwest Region, said the Fish and Wildlife Service has put both issues far down the list of concerns for the greater sage-grouse.
“Neither of those will change the calculus for the Fish and Wildlife Service,” he said.
In a 2010 Federal Register notice, Fish and Wildlife concluded that neither hunting not predation currently poses a significant threat to the species.
The situation is somewhat different for the Gunnison sage-grouse, a far less-numerous species limited to some 5,000 birds centered in Gunnison County, but also extending into Utah. Proposed by Fish and Wildlife to be listed as endangered, it’s been off-limits to hunting in Utah since 1989. In 2000 Colorado ended hunting for the bird in the Gunnison Basin, the only place where it had been allowed.
As for predators, “the best available information shows that predation is currently a threat to the Gunnison sage-grouse and will continue to be a threat to the species,” it said in its endangered species listing proposal posted to the Federal Register this year.
But it added, “Studies of the effectiveness of predator control have failed to demonstrate a long-term inverse relationship between the predator numbers and sage-grouse nesting success or population numbers.”
For the greater sage-grouse, man himself was once a significant predator. Fish and Wildlife estimates that hunters took 2.3 million birds during the 1970s.
Hunting the bird remains legal in 10 of the 11 states where it is found, with Washington prohibiting it. Fish and Wildlife says annual harvest rates dropped to an average of about 31,000 from 2000 to 2007.
Kathy Griffin, CPW’s sage-grouse conservation coordinator, said Colorado has either closed or minimized greater sage-grouse hunting in various areas over the years. Petch said that by comparison, the start of the season for the bird in the 1980s “looked like big-game opening season.”
CPW estimates that the 2011 harvest was 383, give or take about 128, based on hunter survey data. Annual estimates dating back to 1999 range anywhere from around that level to nearly 2,000, in 2004.
An estimated 22,646 sage-grouse lived in Colorado in 2008, Fish and Wildlife says, citing CPW data.
Griffin said hunting of the bird in the state is “very regulated,” and evaluated each year based on spring bird counts. The thinking is that allowing limited hunting in localized areas with populations large enough to sustain it doesn’t pose a species-wide threat to the bird.
Hunting is currently limited to parts of North Park and far-northwest Colorado. Seasons currently vary locally from two days to a week, with daily bag limits of two and possession limits of two to four.
CPW officials say hunting the sage-grouse can be defended in part by the concept of compensatory versus additive mortality. The thinking with compensatory mortality is that sage-grouse not killed by hunting would likely otherwise die of other factors such as winter mortality, rather than hunting contributing to mortality in an additive fashion.
While it doesn’t currently consider hunting a threat to the bird, Fish and Wildlife has said there’s contradictory evidence about whether hunting of greater sage-grouse is indeed compensatory, and that some harvest management levels are established on the assumption that winter mortality is high, when in fact one study showed it’s only about 2 percent.
Jim Cochran, Gunnison County’s wildlife conservation coordinator, said one consequence of ending the hunting there was that scientists lost a major source of information about population, sex distribution, age and other factors that came from bag checks. Griffin also said hunters also serve as advocates for preservation species.
“Sportsmen are the greatest conservationists,” said Luke Schafer, who has been working on the greater sage-grouse issue in Craig for Conservation Colorado.
He said he and plenty of his colleagues are sportsmen and sportswomen, and he doesn’t oppose hunting the bird. But he said they all feel if evidence showed it was detrimental, “we’d be the first in line (to ask CPW) to close the season.”
The issue of hunting arises with other species of concern as well. Fish and Wildlife had considered adding the Gunnison’s prairie dog to the Endangered Species Act before recently deciding it doesn’t warrant such protection. It lives in the Four Corners states, and all four states allow shooting of the animal. But Fish and Wildlife decided that the activity has only localized impacts on the animal, and that measures by states such as seasonal shooting prohibitions have proven effective in helping the species.
As for the idea of predator control, the question when it comes to both greater and Gunnison sage-grouse is where to begin. Raptors, coyotes, ravens, raccoons, badgers, foxes and even elk and domestic cows, along with dozens of other species, are known to feed on the birds or their eggs.
Said Petch, “It is the fate of almost all sage-grouse to be eaten by something at some time.”
One predator-control study was conducted in 2011-12 on a San Miguel County population of Gunnison sage-grouse. Federal officials killed hundreds of coyotes, ravens and other predators, after none of eight marked chicks survived for three months. After predator control, four of 10 marked chicks lived at least two months, and two made it at least a year, although Fish and Wildlife says factors such as weather could explain the difference.
Petch said the experiment had a measurable effect, but cost almost $200,000. To expand that to a population scale and target arguably as many as 30 species would have “a staggering cost,” and cause possible ecosystem harm.
“For a rangewide approach it’s a really challenging approach,” he said.
Griffin notes that sage-grouse evolved as prey and concealment is their best defense. That’s why there’s such a focus on the problems of poor-quality or fragmented habitat, such as that criss-crossed by roads, because that makes the birds and their nests more vulnerable.
Research also indicates landscape alteration has attracted more predators such as red fox to sage-grouse habitat.