Many raptors, the hawks, eagles, and falcons of the world, migrate over long distances, often in impressively large numbers. Many avoid crossing wide expanses of water and follow "flyways" to optimize soaring potential. Atmospheric conditions and landscape features, including waterways and mountain ranges, funnel these birds into predictable bottlenecks through which thousands of daytime birds of prey may pass in a short time. Birders and ornithologists also congregate at these locations to observe the river of raptors passing overhead (as did hunters in the United States in the past and...

Raptors are formally classified into five families and include birds such as eagles, ospreys, kites, true hawks, buzzards, harriers, vultures, and falcons that are familiar and recognized by many observers. These diurnal birds of prey are found on every continent except Antarctica and can thrive in seemingly inhospitable spots such as deserts and the tundra. They have powerful talons and hooked beaks for cutting and tearing meat, and keen binocular vision to aid in their hunting prowess. Because of their large size, distinctive feeding habits, and long-distance flight patterns, raptors...