 |
Long-term assessments of golden eagle nesting density and productivity in the Snake River Birds of Prey National Conservation Area
|
 |
The Snake River Birds of Prey National Conservation Area (NCA) has undergone massive habitat changes since 1980. More than 50% of the shrub habitat has been lost due to wildfires, resulting in large stands of exotic annual grasses (primarily cheatgrass, Bromus tectorum) and forbs. This has resulted in a large-scale reduction in habitat for black-tailed jackrabbits (Lepus californicus), the primary prey for golden eagles (Aquila chrysaetos) in southwestern Idaho. Golden eagle reproduction is closely tied to jackrabbit abundance, and eagle territory occupancy and reproductive success appear to be negatively related to burning. The Bureau of Land Management (BLM) has initiated large-scale reseeding efforts to restore prey habitat for the raptors; however, the effectiveness of these efforts in providing suitable habitat is unknown. Occupancy and productivity data have been collected at all eagle territories in the NCA since 1971, providing a wealth of background information. The NCA is one of very few areas with nearly 30 years of data that are being used to assess status and trend of golden eagles in North America.
This study will continue the long-term assessments of territory occupancy and reproduction of golden eagles in the NCA. These assessments will provide the basis for long-term research to evaluate the effectiveness of vegetation rehabilitation efforts in restoring golden eagle habitat and to understand the mechanisms for responses of nesting eagles to wildfires and other habitat alteration. The overall goal of the research is to obtain information necessary for the BLM to implement the management plan for the NCA and for making management decisions. Results will furnish information to revise the NCA Management Plan and will provide a basis for continued monitoring of raptors, their prey, and habitats in the NCA. Long-term eagle data will be used to assess status and trends of golden eagle populations in North America.
Kochert, M.N., K. Steenhof. 2002. Golden eagles in the U.S. and Canada; status, trends conservation challenges. J. Raptor Research 36: (1 Supplement): 32-40.
Kochert, M.N., K. Steenhof, and M.J. Bechard. 2002. Territory occupancy and productivity of Golden Eagle nesting in the Snake River Birds of Prey National Conservation Area and Comparison Area, 2001. Challenge Grant Cost Share Report. U. S. Department of the Interior, Bureau Land of Management, Lower Snake River District, Boise, ID. USA.
Kochert, M.N., K. Steenhof, J. M. Marzluff, and L.B. Carpenter. 1999. Effects of fire on Golden Eagle occupancy and reproductive success. Journal of Wildlife Management. 63: 773-780.
Steenhof, K., M.N. Kochert, and T.L. McDonald. 1997. Interactive effects of prey and weather on golden eagle reproduction. Journal of Animal Ecology 66:350-362.
These data are preliminary in nature. They have not been approved by the USGS director, and they have not been peer-reviewed. They are provided with the understanding that they are not guaranteed to be correct or complete. Anyone interested in citing this information should contact Mike Kochert before using. Users are cautioned to consider carefully the provisional nature of these data and information before using them. Conclusions drawn from, or actions undertaken on the basis of, such data and information are the sole responsibility of the user.
Mike Kochert
Address: USGS Snake River Field Station
Address: 970 Lusk Street
Address: Boise, ID 83706
Phone: 208-426-5201
E-mail: mkochert@usgs.gov
|
