In North America, migrating raptors travel along several migratory routes, and this site lies on the easternmost route, the Atlantic Coastal Flyway. Birds fly south for the winter from northeastern Canada and the United States, following the Appalachian Mountains and the Atlantic coastline as far as Argentina. Each species migrates on its own schedule, and years of hawk-watching have shown the best times to spot each one. To travel the longest distance with the least energy, raptors use thermals, spiraling high in rising columns of hot air and then gliding until they catch another thermal. They also use slope surfing or slope soaring, riding air deflected upward when north and west winds strike the Appalachian mountain chain, which lets them travel long distances with very little energy.