Routes and travel rates of migrating Peregrine Falcons Falco peregrinus and Swainson's Hawks Buteo swainsoni in the Western Hemisphere

We describe and compare the migration routes, length of migration, and dura tion of migration of Peregrine Falcons Falco peregrinus tundrius and Swains on's Hawks Buteo swainsoni in the Western Hemisphere. We radio tracked migr ants using the Argos satellite system. Our initial samples were 34 Swainson 's Hawks from representative areas of their breeding range, and 61 Peregrin e Falcons captured at nest sites across the North American boreal forest an d low Arctic or on the migration routes along the mid-Atlantic and Gulf of Mexico coasts. The average distance of migration for Peregrines was 8,624 k m southward, and 8,247 km northward. Peregrines travelled at an average I a te of 172 km/d southward and 198 km/d going north. Peregrine Falcons used a t least three broad, general routes south from the breeding areas, and indi viduals stopped migrating as far north as the U.S.A. mid-Atlantic coast and as far south as central Argentina. The radiomarked Peregrine Falcons used coastal routes, mid-continental routes, and water-crossing routes: the Davi s Strait and Caribbean Sea. During northward migration, Peregrines migratin g through at Padre Island, Texas diverged for destinations from central Ala ska across the continent to central West Greenland. Swainson's Hawks migrat ed an average of about 13,504 km southward and 11,952 km northward, and tra velled 188 km/d southward and 150 km/d northward. Swainson's Hawks converge d in eastern Mexico on the Gulf of Mexico Coast. Southward, these hawks fol lowed a narrow, well-defined path through Central America, across the Andes Mountains in Columbia, and east of the Andes to central Argentina where th ey all spent the austral summer. Swainson's Hawks northward migration large ly retraced their southward route.