Migratory birds now challenge sage grouse
August 30, 2013
Speaking the words "sage grouse" in a crowded room of people will likely cause a heated debate. Federal and state agency personnel, landowners, environmentalists, energy developers and agricultural producers all have a vested interest in the future of this controversial game bird. It is common knowledge that greater sage grouse populations have been on a downward trend in recent years. This progression has set a series of studies and management plans into action to save this charismatic game bird, but the direct reason for decline remains unknown.
The U.S. Fish and Wildlife Service (USFWS) has already determined that the greater sage grouse "warrants protection under the Endangered Species Act," but is currently not listed. Probable causes of sage grouse population declines have varied, but researchers have always put 'habitat loss' at the top of the list. The Bureau of Land Management (BLM) lists "loss of sagebrush habitats" as the main cause of the decline in greater sage grouse populations. With Wyoming hosting 37 percent of the world's greater sage grouse population according to data in the June, 2013 PLOS journal, the state elected to create a management plan, which took effect in 2011, to protect critical habitat designated as "core area" in an effort to keep the bird off the endangered species list. This model has been approved by the USFWS and is being adopted by neighboring states with greater sage grouse populations, such as Colorado.
However, current research is revealing a new trend that may also have a negative effect on sage grouse: rising raptor populations. During a study conducted in southwest and southcentral Wyoming, biologists from Utah State University and the University of Wyoming found that sage grouse sought out nest and brood rearing locations with low densities of avian predators, such as golden eagles, magpies, and ravens. The biologists identified Golden Eagles as the main predator of adult sage grouse, and Black-billed Magpies and Common Ravens as predators of sage grouse nests according to a publication of The American Ornithologists' Union. Furthermore, they concluded, "… as avian predators, especially ravens, increase in abundance in sage grouse habitat, high-quality nesting and brood rearing habitat will become more limited."
Wyoming Game and Fish Commissioner, Carrie Little is a landowner in Northeastern Wyoming and has been watching sage grouse population trends for years. She has seen how industry and environmental practices affect sage grouse populations and said that, "For a long time people blamed it [declining populations] on methane, which I think had little or no effect on sage grouse. The only thing that methane probably contributed was when they had standing water. Sage grouse are affected by West Nile Virus; so if they had standing water, like some of the ponds that were created, then the fact that they could have mosquitos that could carry West Nile would have been a contributing factor." Little believes the current biggest threat to sage grouse populations is the high population of raptors in her region.
"Ravens have increased in this state tremendously," said Little. She pointed out studies showing the dramatic effects ravens can have on sage grouse, particularly by predating on nests, then added, "and they're protected by the Migratory Bird Treaty Act, so there's nothing you can do."
Because ravens and raptors are migratory birds, they are protected by federal and state laws. As wildlife species of concern, the BLM with the USFWS has set guidelines and regulations for protecting raptor habitats from disturbance caused by construction and energy development on public lands. These guidelines' objectives according to USFWS researcher Diana M. Whittington, are "… to maintain raptor populations which are stable or improving and enhance raptor populations which are declining …"
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Doug Cooper is a landowner near Casper, Wyo., whose family raises sheep and is involved in energy development. He, too, has watched the changes in sage grouse populations and noticed the increase of predators, specifically raptors, on his land. Much of his land overlaps with sage grouse core areas. To better understand the sage grouse management he is directly involved in, Cooper has been researching and attending public meetings whenever he can. Through this education, he has seen contradicting management philosophies. "You end up with this conflicting idea that they're protecting the raptor who is killing the grouse," he commented.
Answering the question of how to save the greater sage grouse may be as challenging as solving the riddle, "Which came first: the chicken or the egg?" When habitat is preserved, predators increase; and when predators increase, sage grouse suffer. So, what is hurting sage grouse populations: the loss of habitat or the raptors predating them?
If a solution to sage grouse management is never reached and the USFWS finds them worthy of listing as endangered, state managers, energy developers, landowners and all other vested parties will face monumental consequences. The arguing cause of declining sage grouse populations, be it ravens or habitat loss, may no longer matter when federal agencies control the landscape. Commissioner Little commented on the prospect of listing sage grouse, "It would have so many ramifications that it's hard to even imagine what kind of restrictions would be instated."
The bright light at the end of the tunnel may indeed be agriculture. Ranchers preserve large stretches of undeveloped land. This reduces urban sprawl which removes sagebrush habitat. Ranchers assist in the control of predators who feed on sage grouse and at the same time provide an alternate prey source for avian predators. Ranchers maintain water availability in dry, open prairies, and ranchers work with federal and state agencies to not only maintain threatened wildlife species, but also properly manage land. Research into the direct cause of declining sage grouse populations will continue and there likely will be more heated debates, but there are no riddles to solve for ranchers. Whether their land is "core area" or pasture, one "unintended consequence" – positive in this case – of ranching is that wildlife habitat is protected and carefully managed and predators are kept at bay. In many cases this means the chickens keep laying.