Choosing the Route of Bird Migration

Each migratory species generally has a route of travel between its nesting and winter range, but for the majority of species these migration routes are quite broad. Waterfowl tend to be confined to some what narrower corridors determined by the availability of suitable habitat. In fact, it was once thought that there were distinct, narrow flyways (the Atlantic flyway, Central flyway, and so forth) used exclusively by various populations of water fowl. The discovery that birds from one nesting area could be found migrating in several different flyways put that concept to rest.

Although entire species might not be confined to narrow corridors during migration, individual birds often exhibit amazing loyalty to places occupied during previous breeding and non breeding seasons, as well as stopover points between the two, a phenomenon known as site fidelity.

Water birds like these Sandhill Cranes tend to concentrate along narrow migration corridors than do other species. Such corridors often follow major north-south geographic features, such as mountain ranges or river valleys.