Understanding Waterfowl: The Flyways

By Dale D. Humburg

Over the years, I've shot a few banded ducks and geese, reported the band numbers, and looked forward to finding out where the birds were captured and how long they'd lived. I've also enjoyed speculating on the birds' travels between banding and recovery. This has offered me a sense of where I sit in my small corner of the waterfowl world. It's easy, however, to take the information derived from waterfowl banding for granted. The millions of ducks and geese banded over the past century, along with the thousands of birds recovered each year, have provided the foundation for understanding waterfowl biology and the underpinnings of waterfowl management by "flyways."

Flyways can be defined two ways. One is biological, defined by the birds themselves. The other is administrative, developed almost 70 years ago to guide the management of waterfowl harvests and the conservation of the birds' habitats. These definitions are not mutually exclusive. Although we tend to think of flyways in terms of annual hunting regulations, without a solid grounding in waterfowl biology the system wouldn't be scientifically sound.

A Biological Foundation

Frederick C. Lincoln is considered the father of the flyway management system. In his 1935 publication The Waterfowl Flyways of North America, he wrote, "Conservationists now know that the birds have a strong attachment for their ancestral flyways..." His use of banding and recovery locations lent data-based credibility to general observations made earlier in the century on waterfowl migration. Lincoln was careful to make a distinction between migration routes-the individual lanes of travel-and flyways, which encompass many migration routes that together define a geographic area connecting breeding, migration, and wintering areas. He acknowledged that flyways cannot be sharply delineated, especially across the broad expanses of the northern breeding grounds. South of about 45 degrees latitude, however, biological flyways become more distinct as waterfowl funnel through primary fall migration and wintering habitats.

During the mid-1960s, Frank C. Bellrose of the Illinois Natural History Survey further refined our understanding of the waterfowl flyways. Bellrose used the significant increase in available banding data along with observations from aircraft, radar, and state waterfowl surveys to define "flight corridors," which were more specific than flyways. Bellrose also defined the flight corridors used by various waterfowl species groups, including dabbling ducks and diving ducks as well as Canada geese and snow geese, based on their particular migratory affiliations.

Managing Waterfowl by Flyways

Efforts to manage waterfowl by geographic regions began in the mid-1940s. Obviously, ducks and geese do not perceive state borders; however, the biological flyways roughly correspond to these political boundaries. The four administrative flyways, including the Atlantic, Mississippi, Central, and Pacific, were recognized by the U.S. Fish and Wildlife Service (USFWS) in 1947. The flyway system would provide a way to more effectively manage harvest regulations nationally based on waterfowl populations, harvests, and the number of hunters in each of these four regions.

Shortly after the USFWS defined the flyways, states began to become more involved in waterfowl management, especially in regard to harvest regulations, surveys, and research. After World War II, states made great use of federal funding through the Federal Aid in Wildlife Restoration (Pittman-Robertson) Act of 1937 to increase their science and habitat management capacities. This set the stage for more coordinated waterfowl management between the states and the federal government.

There was quite a whirlwind of waterfowl management activity during this formative period. Within just a few years, a formal policy framework establishing the flyway management system was advanced through a resolution in 1951 by the International Association of Game, Fish, and Conservation Commissioners. Less than a year later, flyway councils were established in all four flyways, and a national flyway council was formed to coordinate management across the flyways. In addition, the USFWS appointed representatives to serve as liaisons with the flyway councils. Later, technical or study committees were formed to advise the flyway councils and to help ensure that the best available science was applied in waterfowl management. In the book Flyways, former USFWS Director John S. Gottschalk was quoted as saying, "The flyway councils... were formulated for the express purpose of better waterfowl management. Next to the Migratory Bird Treaties, their creation is the most significant step that has ever been taken in waterfowl management."

Early on, Canadian provinces also saw value in the flyway collaboration and developed working relationships with the states most affiliated with their geography and waterfowl populations. Harvest management is the exception-separate processes for regulating waterfowl harvests exist in each country. However, this international cooperation has been essential in maintaining long-term banding and survey efforts crucial to waterfowl management.

Each Flyway Is Different

Creation of the flyway system standardized harvest management and enabled research and survey coordination to advance. Today, the same general regulations apply to all states or portions of states within a flyway. Although this process is consistent across the nation, each flyway is unique in its geography, hunter numbers, harvest, hunting culture, species affiliations, and waterfowl habitats.

The 17 states that make up the Atlantic Flyway span from Maine to Florida. This flyway is home to about 20 percent of U.S. waterfowl hunters, 10 to 15 percent of the total U.S. duck harvest, and 15 to 25 percent of the total U.S. goose harvest. The Mississippi Flyway includes 14 states stretching from Minnesota to Michigan in the north and Louisiana to Alabama in the south. Nearly half the nation's waterfowl hunters live in the Mississippi Flyway. Thus, it's no surprise that 40 to 50 percent of the U.S duck harvest and 30 to 40 percent of the U.S. goose harvest occur there.

The Central and Pacific Flyways represent the intersection between the biological and administrative aspects of flyways. Ten states are formally part of the Central Flyway, but only the portions of Montana, Wyoming, Colorado, and New Mexico east of the Continental Divide are included. About 20 percent of U.S. waterfowlers live in the Central Flyway, and these hunters harvest a similar proportion of ducks (19 percent), but a disproportionately large number of geese (30 percent). The Pacific Flyway encompasses 12 states (including Alaska) or portions of states west of the Continental Divide. About 15 percent of the nation's waterfowlers reside in this flyway, and these hunters harvest an average of more than 20 percent of ducks, but less than 15 percent of geese, in the United States.

You Are Part of the Flyway System

Much of the information used on an annual basis to manage North America's ducks and geese comes directly from waterfowl hunters. Reporting banded birds ensures that hunting regulations continue to be based on the most current information available. Band recovery data also helps to further refine our knowledge of flyways and migration corridors and track long-term changes in waterfowl distribution. In addition, those who respond to hunting and harvest surveys provide essential insights into the changing human dimensions of waterfowl hunting. Anyone buying a federal duck stamp, whether for hunting or for other reasons, contributes directly to wetlands and waterfowl conservation.