Phil Taylor, E&E reporter
Greenwire: Wednesday, June 4, 2014
In the race to save the greater sage grouse from becoming a threatened or endangered species, state and local officials are increasingly turning their attention to a lesser-known culprit: the common raven.
Idaho and counties in northwest Utah and northeast Nevada have proposed shooting or poisoning ravens to prevent the omnivorous opportunists from devouring sage grouse eggs, which may be nudging the ground-dwelling birds closer to extinction.
But environmental groups have loudly opposed those plans, arguing there’s little evidence that controlling ravens is a viable or cost-effective way to bolster sage grouse.
A better strategy, they insist, would be to reduce or retrofit power poles, stock tanks, buildings and garbage dumps that attract ravens and to focus on what the Fish and Wildlife Service has identified as the grouse’s primary threats: habitat loss and weak regulations.
“It’s just classic scapegoating,” Casey Lott, coastal and waterways program coordinator for the American Bird Conservancy in Boise, said of plans to kill ravens. “There’s no good evidence it’s necessary to protect sage grouse.”
Raven control is just one of the myriad steps state and federal officials are pursuing to put the iconic sage grouse on solid ecological footing ahead of FWS’s court-ordered listing decision due in September 2015.
The Bureau of Land Management, for example, is amending dozens of resource management plans to address threats from energy development and wildfire. And the Agriculture Department is providing financial assistance for landowners to sign conservation easements and improve farming and ranching techniques.
Ravens represent a smaller front in the battle, but it’s one that has gained considerable attention in recent months.
The oil and gas industry earlier this year blasted the Interior Department for “ignoring a substantial body of literature about raven predation” that points to the need for more lethal control.
Months later, Idaho’s Department of Fish and Game announced a controversial two-year study to shoot or poison 4,000 ravens in three areas of the state where sage grouse have taken a nose dive and where raven numbers, as in many parts of the West, have soared.
Power poles in southern Idaho give ravens a leg up in preying on sage grouse and other wildlife, according to government studies. Photo courtesy of the U.S. Geological Survey.
That plan, which was approved by FWS, was scuttled this year after the USDA’s Wildlife Services failed to complete its environmental review in time for the sage grouse nesting season — when ravens congregate. The plan calls for Wildlife Services to distribute thousands of chicken eggs laced with the poison DRC-1339, which federal officials insist won’t harm other wildlife.
The study is slated to resume in 2015.
Late last month, commissioners in northwest Utah’s Box Elder County sent a letter to Interior Secretary Sally Jewell asking that ravens be delisted from the Migratory Bird Treaty Act — which prohibits killing them without a permit — to give federal officials more leeway to control them.
“The greater sage grouse population, currently under consideration for listing under the Endangered Species Act, is severely impacted by common raven predation,” the commissioners wrote. Ravens, the letter notes, have increased threefold in the United States in the past 27 years and by much more in portions of the West.
“Why are we worried about listing a bird that’s being eaten by a bird that’s also listed?” Commissioner Stan Summers asked. “That doesn’t make any sense.”
Summers said Elko County, Nev., across the state line from his county, is sending a similar letter to Jewell.
Can ravens be controlled?
But many, including FWS, are skeptical whether killing ravens is a viable solution for sage grouse. Moreover, the U.S. Geological Survey in a sweeping study on sage grouse released a year ago found that there is “little published support for predation being a limiting factor in sage-grouse populations, particularly in areas where there is high-quality habitat.”
Montana Fish, Wildlife & Parks last summer said predator control for sage grouse is “costly, temporary, risks variable results, and is not likely to avert an ESA listing,” and that maintaining and enhancing intact habitat offer more bang for the conservation buck.
Even Wildlife Services acknowledged that new ravens are likely to move in to replace birds that are killed by the poison in Idaho, which means multiple years of removal would be required.
That was the case in northeastern Nevada, where raven removal resulted in only short-term reductions in raven numbers and opened the door for badgers to increase their predation of grouse, according to a 2007 study.
In addition, a dissertation last year by a graduate student at Utah State University found there was “not a strong connection” between raven removal in southern Wyoming from 2008 and 2011 and increased sage grouse nesting success.
“Nevertheless, predator removal may have a place in sage-grouse management as an interim mitigation measure when sage-grouse populations are subjected to high densities of ravens,” said the dissertation by Jonathan Dinkins. “However, long-term solutions to reduce human-subsidized raven populations are necessary to address the growing raven and sage-grouse conflict.”
Other studies were more encouraging.
One study in 2004 by Peter Coates and David Delehanty at Idaho State University used miniature camouflaged cameras to record sage grouse nesting activities in northeast Nevada in 2002 and 2003 after federal officials had removed several hundred ravens.
Nesting success was 74 percent, which was nearly double what was expected based on 14 previous studies. However, it was not known how successful sage grouse nesting was before the raven control operation began.
The authors concluded that it was “probable” that raven control improved sage grouse nesting success and that predator control efforts could bear fruit in places where sagebrush habitat is undergoing lengthy restoration.
According to Wildlife Services, raven control in Idaho could help sage grouse during the 15 to 30 years it takes for damaged sagebrush habitat to recover and properly conceal the bird’s ground nests.
“Raven predation management warrants testing and evaluation as an interim strategy to address predation problems in three sage-grouse management areas,” the agency notes in its environmental review.
IDFG plans to monitor lek populations before and after the raven poison is administered, said Don Kemner, the agency’s wildlife program coordinator. It is also working with landowners to reduce opportunities for ravens to nest on water towers, old buildings and transmission structures, and to feed on dead livestock and garbage, he said.
Although ravens do not fulfill a critical ecological niche and are nowhere near endangered, environmental groups have strongly opposed lethally removing them.
At best, such efforts are a distraction from conserving sage grouse habitat and, at worst, they could inadvertently harm other wildlife species, groups argue.
The Idaho proposal, for example, “fails to fully examine the direct, indirect and cumulative impacts of using the avicide DRC-1339 across the southern Idaho landscape,” said a letter last month to Agriculture Secretary Tom Vilsack from groups including the American Bird Conservancy and National Audubon Society and the Boise-based law firm Advocates for the West (E&ENews PM, May 5).
Todd Tucci, an attorney for the law firm, said Wildlife Services isn’t following the specific precautions and monitoring mandates required by U.S. EPA to use the poison. The federal government can expect a lawsuit if those protocols aren’t followed, he said.
Caught in the act: A wildlife camera placed by scientists at Idaho State University shows a raven preying on sage grouse eggs. Photo courtesy ISU.
Clait Braun, the former leader of a Wildlife Services national advisory committee, said the Idaho project “is not well-designed nor scientifically supported,” and therefore “no tenable scientific data will be gathered.”
Lott, of ABC, said it is “foolish” to believe raven control is a viable way to save sage grouse, given the predators’ booming population in the West. “The idea of trying to get rid of ravens at some meaningful landscape scale in the West is just crazy,” he said.
Habitat fragmentation and the addition of makeshift perches such as transmission poles have created “preferred habitat” for common ravens, according to a study published earlier this year by the Wildlife Conservation Society, Idaho State University and the U.S. Geological Survey.
The study, published in the journal The Condor: Ornithological Applications, found that more than half of 82 raven nests found on the Department of Energy’s Idaho National Laboratory land in southeastern Idaho were located on transmission poles. An additional 19 percent were in trees, and 14 percent were on other human-made towers.
Raven nesting was reduced farther from the poles, which offered the birds a wider range of vision, greater attack speed and easier takeoff, researchers said.
“By altering the landscape with roads, facility construction, billboards and transmission lines, and in some cases providing sources of water and food, we are ‘subsidizing’ ravens and providing them with the opportunities and advantages they need to excel in areas that they didn’t before,” said lead author Kristy Howe. “This is bad news for the animals in that ecosystem upon which ravens prey.”
Common raven populations have increased more than 300 percent over the last 40 years in the West, in part, according to Lott, “because the table has been set for them.”
Ravens are also preying on the federally endangered desert tortoise, the endangered San Clemente loggerhead shrike and the California least tern, according to WCS.
Another intra-avian battle is playing out in the Pacific Northwest, where the barred owl is threatening to force out the smaller, federally threatened northern spotted owl. It’s a much greater threat than ravens pose to sage grouse.
The Interior Department last July announced plans to shoot about 3,600 barred owls in the region to prop up the spotted owl (E&ENews PM, July 23, 2013).