Arctic Science Journeys
Radio Script
1997

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Fly Away Home
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STORY: At the mouth of Alaska's Copper River, where it empties into the North Pacific Ocean, is a vast tidal mudflat. At low tide the "flats"--as the locals call them--stretch some 500 kilometers, or about 310 miles. For much of the year it is eerily quiet here, except for the bald eagles and the pounding surf.

But for a few weeks each spring the delta is transformed into a moving, noisy oasis. Shorebirds--millions of them--arrive in waves that blacken the sky. They've come from as far away as Australia, Hawaii, and South America. Here they can rest and feed before resuming their journey to their Arctic nesting grounds. Sandy Frost is an interpretive specialist with the U.S. Forest Service.

FROST: "It's really exciting because we do have over 30 different species of shorebirds that come through the delta. The vast majority, probably 80 to 85 percent of the birds, are western sandpipers and dunlins. Of the rest of the shorebirds, though, we get quite a variety. Early in the migration we have blackbellied plovers, we have some golden plovers, and we have short-billed and long-billed dowitchers, we see greater and lesser yellowlegs, and sometimes out on the flats we get to see ruddy turnstones and black turnstones. We see least sandpipers and semipalmated sandpipers, and even sometimes some little semipalmated plovers."

Within a few weeks, some 10 million birds will pit-stop here on the Copper River Delta, making it the most important layover along the Pacific Flyway. That's the route used not just by shorebirds, but by ducks, geese, swans, cranes, songbirds, falcons--even hummingbirds--to migrate from winter ranges in the south to summer nesting areas in the Arctic. Mary Anne Bishop is a federal wildlife biologist.

BISHOP: "For many birds, that's actually their first landfall. That's the first site they come to, they're coming up the coast, here's the first big, big mudflat. So for a bird coming up they're going to see Kayak Island on their left and then they're going to see Controller Bay area and all these mud flats on the Bering River on their right. They're typically pretty tired and they're gonna spend a few days."

Shorebirds are small and long-legged and have slender beaks--and to the untrained eye they look a lot like--most like a common sparrow. They fly in a kind of military precision that would make the Blue Angels nervous. Thousands of birds fly in close formation, darting violently left, then right, finally settling on the sticky brown and gray mud. They're not here for the breathtaking scenery, but for something far more basic--food. The Forest Service's Mary Anne Bishop.

BISHOP: "The western sandpipers are eating a lot of larvae, long-legged fly larvae, and little midges, and they'll also eat beetles, and macomas, Macoma baltica, they're these little pink clams that they'll eat. And the dunlins, they'll particularly eat the pink clams. A lot of the other species are eating the marine worms, the polychaetes, clams, all sorts of things out there."

Making the journey north requires careful timing. If they leave too late their chicks may not be old enough to fly before the short Arctic summer ends. Poppi Benson of the U.S. Fish and Wildlife Service says shorebirds have a plan.

BENSON: "I think one of the fun things is that they go to the Arctic before there is any food there, just to get started on the egg laying, and they get up there before the insects hatch so as soon as the chicks are born, they are ready to feed them all that good stuff."

Some birds are in a hurry to get to the Arctic. The Pacific golden plover can make the 3,500-mile journey from Hawaii in just four days. Biologists once thought such a trek required huge amounts of energy. Not so, says Mary Anne Bishop.

BISHOP: "Everyone thought that okay these birds have to be super fat so they have enough energy to move up. Well, what we're beginning to find is really for a lot of these birds, for what they weigh when they get to places like the Copper, they aren't burning all that fat up. What we think is happening is that they're catching good tailwinds."

Almost as suddenly the birds arrive on the delta, they're gone. Radio tracking studies indicate the birds stay just a couple of days--long enough to fill their bellies and catch their breath before taking wing again. Soon, an eerie stillness descends on the delta. Until next year.

OUTRO: For Arctic Science Journeys, this is Debra Damron reporting from Fairbanks, Alaska.