干旱区生态环境知识资源中心

The influence of prairie dogs (Cynomys spp.) on the population status and ecology of nesting ferruginous hawks (Buteo regalis) has been poorly documented. Based on aerial and ground surveys and GIS mapping, we examined spatial relationships between nesting ferruginous hawks and colonies of Gunnison’s prairie dogs (Cynomys gunnisoni) in 2 grassland ecosystems of New Mexico: the Estancia Valley in 1999 and 2000, and the Plains of San Agustin in 2000. The numbers of occupied nests and prairie dog towns were greater in the Estancia Valley than the Plains of San Agustin, while median distance to nearest prairie dog town from nests was greater in the Plains of San Agustin. There was a positive spatial association between nests and prairie dog towns in the Estancia Valley in both years, and mean productivity was higher for nests <2 km from the nearest prairie dog town. Furthermore, there was a linear relationship between relative abundance of prairie dog prey remains (relative to other prey taxa) collected from nests and proximity to nearest prairie dog town and between nest productivity and relative abundance of prairie dog prey remains. Nests in the Plains of San Agustin exhibited a negative spatial association with prairie dog towns. We attribute differences between the study areas to abundance of prairie dogs and availability of nest sites in the vicinity of prairie dog towns. Results suggest that prairie dogs can have a significant effect on nest-site selection, abundance of nesting pairs, and productivity of ferruginous hawks in arid grasslands of the American Southwest. Efforts to conserve breeding populations of this top predator where they occur on private or public rangelands in this region should include management of healthy prairie dog populations and the preservation of suitable nesting substrate within the vicinity of prairie dog towns.