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Mighty Migrants

Meet the Black-bellied Plover, a male in breeding plumage, likely on his way to the Arctic, where most plover journey to find a mate, nest, and incubate a nest of eggs. I found and photographed the plover you see, above, more that a dozen years ago, while visiting Fort Desoto along Florida’s Gulf coast.

Every year millions of shorebirds gather in large flocks, departing their southern territories in early spring and heading for breeding areas in northern Alaska and Canada. Black-bellied plovers join Golden plovers, Semi-palmated plovers, Wilson’s plovers, sandpipers, godwit, red knot, and other shorebirds on long-range migrations. The birds often molt into their breeding plumage enroute, and stop briefly along the way at beaches and other staging areas to rest and fatten up for days of non-stop flight.

How far do the birds travel? Until recently, biologists depended on data collection from birders (both professional and amateur), bird banding, and other sources to speculate on the distances birds flew as part of annual migrations. But now, scientists have state-of-the-art tools to measure bird migrations. Thanks to satellite transmitters and the GPS satellite network, biologists can determine not only how far birds have flown during migration but also the exact route they’ve taken.

Consider, for example, the case of “Number 97,” a Pacific Golden Plover (a shorebird in the same genus—Pluvialis—as the Black-bellied Plover, above). Wally Johnson, a biologist who has been studying birds for almost four decades, captured the Plover on its nest near Nome, Alaska, on June 14, 2014, and fitted him with a small satellite transmitter.

After a successful breeding season, the Plover left the tundra in early September “and flew south to the Yukon-Kuskokwim Delta. There he joined thousands of other shorebirds as they prepared to migrate to places throughout North and South America, Asia and Oceania.” Migrating birds stop at such staging areas to bulk up, nearly doubling their weight in preparation for the trip ahead by gorging on such avian delicacies as small mollusks, worms, horseshoe crab eggs, crustaceans, and insects.

On 15 September,” writes Eric Wagner in “The Epic Journeys of the Plover” for Cosmos magazine, Number 94 left the Yukon delta “and flew towards Hawaii, following a direct route until he was above the archipelago, when he veered west, perhaps to skirt a storm. He traced a shallow arc across the Pacific Ocean, covering more than 8,800 kilometres [5,468 miles] before he landed in Okinawa, Japan, on 23 September. It was the first time he had touched land in eight days.”

By the time Number 97 completed his migration, arriving in Nome “at 9pm on 31 May 2015,” the plover had flown 27,000 km (nearly 17,000 miles). The American Golden Plover, a slightly larger cousin of the Pacific Golden Plover, travels even further, migrating more than 45,000 km (or 25,000 miles) annually, including 3,900 km (2,400 miles) over open water.

Keep in mind that the circumference of the Earth at the equator measures 40,075.16 km (or 24,901.55 miles).

A pretty amazing feat for a bird that weighs about 7 ounces and about 10 inches long (close to the size of a starling), wouldn’t you say?

You can read more about migrating shorebirds (and the earth’s circumference) in the following articles:

The Story of Number 97
The Grey or Black-bellied Plover
Arkive on the American Golden Plover
Audubon on the American Golden Plover
Wikipedia on the American Golden Plover
Audubon on the Pacific Golden Plover
Wikipedia on the Pacific Golden Plover
The Magnificent Shorebird Migration

How Many Miles Around the Earth?