Welcome toBoulder County Nature Association - Winter Raptor Surveys

Since1983 Boulder County Nature Association (BCNA) volunteers have counted winteringraptors along survey routes scattered throughout the plains of Boulder County,Colorado. We initiated the surveys during a time when intensified poisoningefforts by private landowners and government agencies appeared to threatenprairie dog populations in parts of Boulder County. Some of these poisoningswere occurring in the Boulder Reservoir area, where Ferruginous Hawks,Red-Tailed Hawks, and Bald Eagles gathered each winter. We wanted to observethe effects of fluctuating prairie dog populations on these and other species.We also hoped to locate wintering raptor concentration areas, such as BaldEagle roosts, Northern Harrier roosts and large prairie dog colonies, so thatthese areas could be protected. In the intervening 40+ years, this communityeffort has created a robust dataset of winter raptor abundance, speciesrichness, age demographics, and land use, helping us understand how BoulderCounty can best support our wintering raptor populations.