Raptor Nest Use in Relation to Coal-bed Methane Development in Wyoming

More than 15,000 coal-bed methane (CBM) wells have been constructed over the past ten years in the Powder River Basin of northeastern Wyoming, USA. This development overlaps breeding territories of at least 19 raptor species, with largely unknown consequences to raptor nest use and success. Our objectives were to determine 1) temporal and spatial trends in raptor nest occupancy in relation to CBM development, and 2) local habitat characteristics that may mitigate disturbance caused by energy development. Using nest locations for 19 raptor species and the locations of CBM wells constructed in the Powder River Basin from 2003-2011, we quantified the level of energy development impact to each nest. Then, using associated nest use data, we compared the nest use of impacted and non-impacted nests. Preliminary analysis showed that raptor nest use (for all species pooled) decreased as CBM well development occurred at closer proximities to the nest, and nest use gradually increased with time since initial well construction. At the species level, red-tailed hawks (Buteo jamaicensis), great-horned owls (Bubo virginianus), golden eagles (Aquila chrysaetos) and ferruginous hawks (Buteo regalis) exhibited patterns similar to those described above; however, the effect of CBM development may be influenced by local topography and habitat type. Our results will assist land managers seeking to balance the needs of raptor populations with energy extraction activities, and provide insight into species-specific tolerance levels for disturbance associated with energy development. Jason Carlisle, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology, University of Wyoming, Dept. 3166, 1000 E. University Ave., Laramie, WY 82071 jason.d.carlisle@gmail.co