Documenting Year-round Movements of Swainson's Hawks

Most swainson’s hawks migrate between North American breeding grounds and South America, but little is known about their migration, use of stopover areas, and movements on the pampas of South America. USGS scientists characterized the annual patterns of long-distance movement and delineated migration routes of 46 hawks tagged in separate nesting areas throughout their breeding range. Satellite telemetry tracking the hawks showed they followed three main routes south, converged along the east coast of central Mexico, and then followed a narrow corridor to an area in central Argentina. Departure dates, length of both northward and southward migrations, stopover sites, and movements within Argentina were identified. Documenting year-round movements of birds that migrate long distances is required to identify factors that contribute to their survival and to develop international conservation strategies.