Just passing along some info.
West Nile Virus and Greater Sage-Grouse
By: David Naugle and Brett Walker
Wildlife Biology Program, University of Montana, Missoula, MT 59812
Since 1999, West Nile virus (WNV) has rapidly spread west across North America, infecting and killing humans, horses, and at least 208 species of birds. The virus has reached 48 U.S. states, seven Canadian provinces, Mexico, and the Caribbean, and it continues to spread. Surprisingly, the impact of WNV on survival in native, wild bird populations is virtually unknown. Following discovery of the first case of WNV mortality in greater sage-grouse on 24 July 2003, we directed a rapid, coordinated effort between U.S. and Canadian biologists and land managers to assess the impact of WNV on sage-grouse in the eastern half of their range. We observed mortalities caused by WNV infection among radio-marked female greater sage-grouse from four studies in Alberta, Montana, and Wyoming between 1 July-31 August 2003. Of 22 testable carcasses from across 4 studies, WNV was confirmed as the cause of death in 18 cases. Although we cannot release specific numbers from survival analyses without confirmation from the scientific peer-review process, we do know that if our marked samples are representative of broader impacts of WNV, the virus may be an important new stressor on sage-grouse populations. Of immediate concern are the potentially devastating consequences of WNV for small populations of Gunnison sage-grouse (C. minimus) in Colorado and Utah and greater sage-grouse in California, Utah, Washington, Alberta, and Saskatchewan. In our survey of birds from Alberta, Montana, and Wyoming this past fall from areas with confirmed WNV deaths, no live greater sage-grouse tested seropositive for neutralizing antibodies against WNV, indicating that birds have little or no innate immunity to the infection. Our mosquito trapping in the Powder River Basin in Wyoming indicated that the mosquito Culex tarsalis, a highly competent vector of WNV, was the most common mosquito breeding in ponds throughout our study sites, and many were infected with the virus. The emergence of WNV will undoubtedly intensify biological and political debates over how to best maintain large areas of high-quality sage-grouse habitat needed to support robust, genetically diverse populations capable of withstanding stochastic disease events. The impetus for WNV work is from a study to evaluate potential impacts of coal-bed methane development on greater sage-grouse in the Powder River Basin of Wyoming and Montana. This work is through the University of Montana’s Wildlife Biology Program and is currently funded by the Bureau of Land Management. We plan to continue our research in the Powder River Basin to investigate impacts of WNV and coal-bed methane development on greater sage-grouse. Plans include trapping and marking >100 more birds this spring for study into the year 2006. There are so many people and organizations that made this effort possible. Following are acknowledgments of the organizations that people work for: University of Alberta, Wyoming State Veterinary Laboratory, Boone and Crockett Wildlife Conservation Program, University of Montana, University of Wyoming, Montana State University, USDA-Arthropod-borne Animal Diseases Research Laboratory, U.S. Fish and Wildlife Service, Wyoming Game and Fish Department, and the Bureau of Land Management.
West Nile Virus and Greater Sage-Grouse
By: David Naugle and Brett Walker
Wildlife Biology Program, University of Montana, Missoula, MT 59812
Since 1999, West Nile virus (WNV) has rapidly spread west across North America, infecting and killing humans, horses, and at least 208 species of birds. The virus has reached 48 U.S. states, seven Canadian provinces, Mexico, and the Caribbean, and it continues to spread. Surprisingly, the impact of WNV on survival in native, wild bird populations is virtually unknown. Following discovery of the first case of WNV mortality in greater sage-grouse on 24 July 2003, we directed a rapid, coordinated effort between U.S. and Canadian biologists and land managers to assess the impact of WNV on sage-grouse in the eastern half of their range. We observed mortalities caused by WNV infection among radio-marked female greater sage-grouse from four studies in Alberta, Montana, and Wyoming between 1 July-31 August 2003. Of 22 testable carcasses from across 4 studies, WNV was confirmed as the cause of death in 18 cases. Although we cannot release specific numbers from survival analyses without confirmation from the scientific peer-review process, we do know that if our marked samples are representative of broader impacts of WNV, the virus may be an important new stressor on sage-grouse populations. Of immediate concern are the potentially devastating consequences of WNV for small populations of Gunnison sage-grouse (C. minimus) in Colorado and Utah and greater sage-grouse in California, Utah, Washington, Alberta, and Saskatchewan. In our survey of birds from Alberta, Montana, and Wyoming this past fall from areas with confirmed WNV deaths, no live greater sage-grouse tested seropositive for neutralizing antibodies against WNV, indicating that birds have little or no innate immunity to the infection. Our mosquito trapping in the Powder River Basin in Wyoming indicated that the mosquito Culex tarsalis, a highly competent vector of WNV, was the most common mosquito breeding in ponds throughout our study sites, and many were infected with the virus. The emergence of WNV will undoubtedly intensify biological and political debates over how to best maintain large areas of high-quality sage-grouse habitat needed to support robust, genetically diverse populations capable of withstanding stochastic disease events. The impetus for WNV work is from a study to evaluate potential impacts of coal-bed methane development on greater sage-grouse in the Powder River Basin of Wyoming and Montana. This work is through the University of Montana’s Wildlife Biology Program and is currently funded by the Bureau of Land Management. We plan to continue our research in the Powder River Basin to investigate impacts of WNV and coal-bed methane development on greater sage-grouse. Plans include trapping and marking >100 more birds this spring for study into the year 2006. There are so many people and organizations that made this effort possible. Following are acknowledgments of the organizations that people work for: University of Alberta, Wyoming State Veterinary Laboratory, Boone and Crockett Wildlife Conservation Program, University of Montana, University of Wyoming, Montana State University, USDA-Arthropod-borne Animal Diseases Research Laboratory, U.S. Fish and Wildlife Service, Wyoming Game and Fish Department, and the Bureau of Land Management.
