Shorebird Migration Flyways
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Flyways—Sky Paths The migratory routes of birds, referred to as flyways, are not specific, narrow “highways.” Instead, they are general routes that most migrants tend to follow. Scientists have proposed that birds use the stars, the sun, and even the Earth’s magnetic field for guidance. Many shorebirds follow coastlines. Two flyways, the American Pacific and the American Atlantic, follow the coasts of the North American continent. They extend from the Alaskan and Canadian Arctic, along the Pacific and Atlantic coasts to the southern tip of South America. In North America, shorebirds also migrate inland along the American Central Flyway. Other shorebird migration routes that use the North American Arctic include the Central Pacific and the East Asian-Australasian Flyways. The Central Pacific Flyway extends across the ocean from New Zealand to Pacific islands like Hawaii and up through the Alaskan Arctic. The East migrating shorebirds will return few stopover sites, a bottleneck Asian-Australasian Flyway runs to the same stopover site year results at these few vital wetlands. from Australia, along the east after year. Termed staging, these These critically important staging of the Asian continent, through large flocks of shorebirds will feed areas can host tens of thousands, countries such as Japan, China, and for several days or weeks in order even hundreds of thousands, of Korea, to the Russian and Alaskan to build up their energy reserves shorebirds at one time. In fact, five Arctic. to continue their flight. Wetland sites in North America support estuaries, rich habitats where a more than a million shorebirds each Migrating Shorebirds source of freshwater meets the spring. Stop to Rest and Feed ocean, provide some of the most Most migrating birds require important shorebird staging areas the presence of wetlands in their in the world. breeding habitat and on their wintering grounds. These two Arctic-nesting shorebirds are also regions are often thousands of famous for the huge numbers of miles apart. Shorebirds depend birds that concentrate at stopover on wetlands in between for food sites along the flyway. Since most and rest to reach their final Arctic-nesting shorebirds tend to destinations. Large numbers of use the same relatively S H O R E B I R D S M 70 I Explore the World with Shorebirds! S A T R ER G S RO CHOOLS P Shorebirds Congregate at Migrating Shorebirds Important Staging Areas! Critical Staging Areas of North Are Extremely Vulnerable! America If a traditional stopover is lost ■ The Copper River Delta is to development or contaminated thought to be the most heavily Pacific Flyway with pollution, the birds do not used stopover site for all Copper River Delta, Alaska have the energy or the time to look Western Sandpipers along the Kachemak Bay, Alaska for another suitable place to stop. Pacific Flyway. Shorebirds Mono Lake, California Sometimes an entire population stop at this site because of the Salton Sea, California will move through a stopover site superabundance of crustaceans, San Franciso Bay, California within a week or two. This makes mollusks, worms, and other Gray’s Harbor, Washington shorebirds extremely vulnerable energy-rich foods. Great Salt Lake, Utah to habitat changes or loss. One Lahontan Valley, Nevada environmental disaster at a ■ Shepody Bay, in the Bay of Fundy, critical staging site could impact is another important shorebird Central Flyway the survival of an entire species of site for at least 34 species of Cheyenne Bottoms, Kansas shorebird! shorebirds that use the marshes Sand Lake, South Dakota and mudflats. About one million Quill Lake, Saskatchewan Explore the World with Shorebirds! Semipalmated Sandpipers visit Bolivar Flats, Texas Discover the mysteries and this stopover site along the Quivira NWR, Kansas challenges of migration through Atlantic Flyway from mid-July Rainwater Basin, Nebraska math, simulation games, and to early September. Horicon Marsh, Wisconsin creative writing using these activities: ■ Cheyenne Bottoms, considered Atlantic Flyway ■ Migration Headache the largest interior marsh in Delaware Bay, New Jersey, ■ Migration Math Madness the United States, hosts as Delaware, Maryland ■ The Incredible Journey many as 45 to 90 percent of all Bay of Fundy, Canada ■ Precarious Paths our shorebird, duck, and geese Maryland/Virginia Barrier ■ Bird’s-Eye View species that stop to rest and feed Islands during their migration along the Cape Romain NWR, South Central Flyway. Carolina Monomoy Island, Massachusetts S H O R E B I R D S M 71 I Explore the World with Shorebirds! S A T R ER G S RO CHOOLS P The Shorebird Flyways in Your Backyard What is a Migration Flyway? A migration flyway is an invisible “highway in the sky,” a general route birds follow as they fly from their breeding grounds in the north to more southern areas where they spend their winters. How Did Scientists Determine Where the Flyways Are? Biologists have determined migration routes through the use of radio telemetry and observation of banded and flagged birds. For some species, they can even tell where birds are from by bill length and coloration. Many shorebirds that have been banded have also been flagged. This is a band that sticks out from the side of the bird’s leg. Each country has an assigned color so biologists can determine where the birds have come from. For more information on the flagging program go to http://www.mb.ec.gc.ca/ nature/migratorybirds/pasp/ dc29s01.en.html. Where Are These Flyways Located? Scientists have grouped these flight paths into generalized flyways. Asian-Australasian Flyways. The American Atlantic Flyway is really When talking about migration Central Pacific Flyway extends on the western side of the Atlantic flyways, biologists have most often across the ocean from New Zealand Ocean and should be called the referred to the routes of waterfowl to Pacific islands like Hawaii, and Western Atlantic Flyway. However, that follow four fairly narrow up through the Alaskan Arctic. The we felt that would confuse our migration paths through North East Asian-Australasian Flyway primary audience which is in America: the Pacific Flyway, the runs from Australia, along the east the United States. By adding Central Flyway, the Mississippi of the Asian continent through “American” to Atlantic Flyway, Flyway, and the Atlantic Flyway. countries such as Japan, China, and people will understand that we are Korea, to the Russian and Alaskan speaking of the Atlantic flyway in Shorebird flyways are more Arctic. the Americas. general and tend to overlap. For this reason, shorebird biologists Flyway Names Interested in more information have identified three broader You will notice that the flyways about the flyway in your backyard? shorebird flyways within North are named with “American” at the The following pages describe the America: the American Pacific beginning. This is to clarify that geographic zones and highlight Flyway, the American Central these flyways are located in the exciting shorebird facts about the Flyway (which combines the Western Hemisphere. Without area where you live. Central and Mississippi flyways of that clarification, people from songbirds and waterfowl), and the other countries may look at this How Do Birds Find Their Way? American Atlantic Flyway. Other information and confuse these Birds probably use a variety of shorebird migration routes that use flyways with other regions of the methods to navigate. Though the North American Arctic include globe. For example, if you take scientists are not exactly sure how the Central Pacific and the East into account the entire globe, the birds navigate along these routes, S H O R E B I R D S M 72 I Explore the World with Shorebirds! S A T R ER G S RO CHOOLS P there are several theories. Some Where Are Important Shorebird For answers to more questions think birds find their way using the Stopover Sites Located? commonly asked about shorebird stars as a guide. There is evidence Important stopover areas are migration and adaptations, that some large flocks of migrating located along each flyway. Some please refer to the sections The birds have seemed to “lose their are famous, like the Copper Magnificent Shorebird Migration way” over large metropolitan areas River Delta in Alaska, for the and Shorebirds Have Special where city lights brighten the sky hundreds of thousands of birds Adaptations in the Shorebird and make the stars harder to see. that stop each year; other sites Primer. Other scientists believe that birds are smaller but just as important. migrate using an internal magnetic Today pollution, development, and Explore the World with Shorebirds! compass. This system guides the agriculture expansion threaten Have students identify the birds along the earth’s magnetic to wipe out many shorebird shorebird flyway(s) they live in. routes. stopover sites. The Western Use the WHSRN site listings Reserve Network (WHSRN) is a found later in this section or How Are Shorebirds Able to Migrate multinational coalition of scientists log on to the WHRSN Web site Such Long Distances? and conservationists working (www.manomet.org/WHSRN/) Shorebirds have specific physical together to identify important sites to identify important shorebird adaptations for long distance flight, for protection. Sites nominated stopover sites in their flyway. including long, pointed wings into the WHSRN network fall Then have your students mark and the ability to gain and store into one of three categories: them on a wall map of North highly concentrated fat to fuel their Hemispheric Sites that host a America. Students can learn journey. Some shorebirds can fly minimum of 500,000 shorebirds specific information about the site’s nonstop for thousands of miles to annually, International Sites with resources from the WHSRN Web reach their migratory destinations. a minimum of 100,000 shorebirds site.