Many species of birds migrate between wintering grounds in the south and breeding grounds in the north. The common routes that migratory birds use to move from one place to another are called flyways. Flyways are routes that have historically provided migrating birds with food and water along the way, as well as suitable habitat and resting places. Each season, more than 100 million North American birds use a flyway to migrate.
The Mississippi Flyway
The Mississippi flyway is the longest overland flyway in North America. It is a critical migratory route for North American birds, especially waterfowl. The Mississippi Flyway begins in the Arctic Circle and northern Canada and includes areas in the United States from the plains to the Great Lakes and on to the Gulf of Mexico.
The northern region of the Mississippi flyway is used by migratory birds as nesting and breeding grounds. The swell of insect and plant life in the short, northern summer provides ample food for the new nestlings and their parents. The northern region of the Mississippi flyway is also safer for rearing young. Since fewer predators are able to withstand the harsh northern winters, migratory birds and their nestlings are less vulnerable to predators.
The upland areas and farm fields of the northern region can provide grains and seeds to supplement migratory bird diets. As winter weather moves south, migratory birds move south with mild weather to stay on open water and stick to sources of food. The consistent water sources of the Mississippi flyway—wetlands, lakes and rivers—provide a corridor of suitable habitat for the birds to migrate.
Wetlands (also called marshes, swamps, bogs and fens) are ecosystems dominated by the presence of water, whether permanent or seasonal. Almost half of all bird species depend on wetlands for survival, whether for water, food supplies or shelter. Waterfowl are especially dependent on surface water for their needs. The wide river bottoms and marshes in the Mississippi flyway provide a reliable source of food, habitat and resting places for millions of migrating waterfowl.
Many of North America's wetlands were drained for agricultural use or development, and forests have been harvested or destroyed. Fewer wetlands and forests mean that migrating birds are being concentrated in small areas, competing for scarce resources. Fewer forests and woodlands also mean fewer stopover points for migrating songbirds. Many songbird species depend on berries and other foods for energy as they migrate. If stopover points are destroyed, birds cannot "refuel" along the way.