LONG-RANGE MOVEMENTS AND BREEDING DISPERSAL OF PRAIRIE FALCONS FROM SOUTHWEST IDAHO

From 1999–2003, we tracked movements of adult female Prairie Falcons (Falco mexicanus) using satellite telemetry to characterize long-range movement patterns and breeding dispersal. We radio marked 40 falcons from April–May on their nesting grounds in the Snake River Birds of Prey National Conservation Area in southwest Idaho. All falcons with functioning transmitters left the Snake River Canyon from late June through mid-July. Most headed northeast across the Continental Divide to summering areas in Montana, Alberta, Saskatchewan, and the Dakotas. Prairie Falcons stayed at their northern summer areas for 1–4 months before heading to the southern Great Plains or to southwest Idaho. The Great Plains was a key migration pathway. Important wintering areas included the Texas Panhandle and southwest Idaho. Most falcons completed their seasonal migrations within 2 weeks. Use of widely separated nesting, summering, and wintering areas appears to be a strategy to exploit seasonally abundant prey resources. Most falcons had three or fewer use areas during the nonbreeding season, and falcons showed a high degree of fidelity to their use areas during each season. At least 21 falcons returned to nest within 2.5 km of where they nested in the previous year, but one falcon moved to a new nesting area 124 km south of her previous breeding area. Prairie Falcon movements suggest large-scale connectivity of grassland and shrubsteppe landscapes throughout western North America. Conservation of Prairie Falcons must be an international effort that considers habitats used during both nesting and non-nesting seasons. Movimientos de Largo Alcance y Dispersión Reproductiva de Falco mexicanus del Sudoeste de Idaho Resumen. Entre los años 1999 y 2003, seguimos los movimientos de hembras adultas de Falco mexicanus utilizando telemetría satelital para caracterizar los patrones de movimiento de largo alcance y la dispersión reproductiva. Marcamos con radios a 40 halcones desde abril hasta mayo en sus sitios de nidificación en el Área de Conservación Nacional de Aves de Presa Snake River en el sudoeste de Idaho. Todos los halcones con transmisores funcionando dejaron el cañón de Snake River desde fines de junio hasta mediados de julio. La mayoría se dirigió hacia el noreste a lo largo de la línea de división continental rumbo a las áreas de veraneo en Montana, Alberta, Saskatchewan y Dakotas. F. mexicanus permaneció en sus áreas de veraneo del norte durante 1 a 4 meses antes de dirigirs