Unlocking Migration's Secrets

Unlocking Migration's Secrets

For centuries the study of bird migration has been riddled with mystery and unanswered questions: Where do birds go in winter? How far do they fly? Can they navigate a hurricane? Scientists are tapping new technologies to find the answers, and transforming everything we know--or think we know--about birds.

By Scott Weidensaul/Photography by Joel Sartore
Published: March-April 2012

For Hope the whimbrel--resting on Cape Cod after surviving her passage through Tropical Storm Gert, her transmitter sending regular reports back to Fletcher Smith and Bryan Watts at the Center for Conservation Biology--the journey was far from over. After pausing just a day, she flew down the coast to the Eastern Shore, lingered a month on the same mudflats and salt marshes where she was originally tagged, then on September 9 flew out over the sea. Late summer was a bad time to be aloft on the western Atlantic, however. Another whimbrel tagged by Watts and his partners, a female named Goshen, normally puddle-jumps from the Eastern Shore to the northeastern coast of South America near Belem, Brazil. Instead, on August 22, she hit the violent eastern edge of Hurricane Irene, then a Category 3 storm, and three days later made an emergency landing on the island of Antigua.

A third female whimbrel, named Machi, which also normally flies nonstop from Virginia to Suriname and eastern Brazil, rode out Irene on the Eastern Shore, then took off only to get tangled up with Tropical Storm Maria before making a safe landfall on the island of Montserrat. Back in Virginia, Smith and Watts were watching the satellite tracks with worry and breathless wonder--seeing how the fragile birds cut through some of the most ferocious storms on the planet and survived. Through the Internet, on which the birds' travels could be followed in real time as colorful dots traversing a map of the hemisphere, uncounted others were able to share in the drama, too.

"Most of these birds are entering the storms on the northeast quadrant, where the winds are in their faces, and then going straight through the eye of the hurricane," Smith says. "It looks like these whimbrels are strong enough to negotiate even these huge storms."

Strong but not invulnerable. Wrung out by their journeys, both Machi and Goshen began island-hopping down the Lesser Antilles instead of flying the rest of the way to South America in a single leap. On September 12, both birds independently approached Guadeloupe, a French-controlled island--which, like several islands in the Antilles, maintains a tradition of legal, basically uncontrolled shorebird hunting.

Tired and hungry, the two birds zeroed in on some of the only wetland habitat on the island--so-called "shooting swamps," where middle- and upper-class Creole hunters watch the weather, and wait for storms to ground exhausted shorebirds. There are 3,000 such hunters on the tiny island, dozens of whom ring the shooting swamps at a time, sitting in lawn chairs with shotguns ready for yellowlegs, dowitchers, semipalmated sandpipers, and other migrants. Other gunners patrol freshly cut sugarcane fields, where upland sandpipers and American golden-plovers feed.

Machi and Goshen both died before they could even land on Guadeloupe. Their deaths enraged conservationists--and provided a tragic reminder that even the briefest portion of an annual cycle can have devastating consequences for a migratory bird.

Are the steady declines in whimbrels, semipalmated sandpipers, and several other shorebirds due to the heavy but--until now--little-known hunting pressure these species face on a few Caribbean islands and along the South American coast?

"Clearly, what's going on down there is a throwback to an earlier time," Watts says. "We hunt woodcock and snipe up here, but it's a managed hunt, and we have good data to back it up. This is an open-ended hunt--there's no bag limit. In just one fallout last year, 2,000 to 3,000 golden-plovers were shot; one hunter said he killed a hundred in a single day. This is legal open-ended hunting."

If there's a bright side, it's that the very public deaths of two well-known migrants is finally spurring an examination of the unregulated shooting on Guadeloupe and elsewhere in the Caribbean. The local newspaper even covered the whimbrels' death, labeling the hunters "murderers," and there are indications that whimbrels and red knots may be added to the list--widely ignored by gunners--of protected species. On Barbados (an independent country where the last Eskimo curlew--the whimbrel's closest relative--was shot in 1963, and which is also a gunning hotspot), one shooting swamp is being bought and converted to a sanctuary.

And what of Hope? She also had to contend with Tropical Storm Maria, her second major gale of the autumn, but she averaged 31 mph through even the worst parts of the storm. On Sept. 14--83 hours and 1,624 miles after leaving Virginia, and nearly 6,000 miles from her nesting site in the Northwest Territories--she made landfall on the island of St. Croix.

There she found a very different world than the gauntlet that awaits migrant shorebirds on islands like Guadeloupe, Martinique, and Barbados. As one of the U.S. Virgin Islands, St. Croix is subject to U.S. laws, including the international treaty that protects shorebirds and to which French possessions like Guadeloupe are not signatories.

Yet even though Audubon and BirdLife International recognize Hope's favored wintering site--a St. Croix mangrove swamp known as Great Pond--as an Important Bird Area, a huge resort development has been proposed that would essentially envelop the bay. Local environmentalists have stalled that project thus far, but disturbance by four-wheel-drive vehicles and illegal dumping are ongoing problems. There are many dangers for a migratory bird, and only a few come out of the barrel of a gun.

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I have tears in my eyes as I

I have tears in my eyes as I type. What a story. Fly safely little Hope & let us all have hope that others will survive senseless hunters.

Whimbrel trek

Great article. Reminds me of how I feel about my ultra-trailrunning, likening it to a migration is a most excellent of analogies. Thanks for sharing this trek of the whimbrel.

Incredible research

What a great article! I love reading about wildlife research and keeping myself up to speed on the current conservation issues. I studied wildlife conservation at the university of Illinois at Champaign-Urbana and participated in a number of research projects through the Illinois Natural History Survey, including one study on the American Golden Plover. I tracked transmitted plovers using radio telemetry during one of their migration stop over spots in Arcola, Illinois. These awesome shorebirds fascinated me in their incredibly long migration and how each year they return to the same stop over spots on their journey, just like the whimbrels. The data I collected just gave us a small glimpse into one part of their migration. To read about this new tracking system with the whimbrels that gave the researchers constant real time locations is absolutely incredible. What an awesome data set and comprehensive look into these birds migration. Knowing this new information about their journey can really help us understand how to conserve this species.

How do I locate the sources

How do I locate the sources you use in your articles. I am interested in studying this topic further. Do you provide the references on your web page somewhere? I don't seem be able to find a link anywhere.

Beautifully written article.

Beautifully written article. Once again I am dropped to my knees in amazement and reverence for the birds-the fierce determination and drive to survive. We must become a global village where every culture understands we can not continue to do what we have always done-i.e. hunt relentlessly with ignorant abandon. It is not imposing our values on another culture, but teaching a higher consciousness of thinking and understanding how all things are related, the balance of life on this planet is so out of whack with too many people. What befalls the animals and nature, befalls us all. Perhaps it is more "manly" to protect and stand up for what is good and right, than to destroy and kill everything in sight.

Life on Earth

It won't make much difference if the tar sands oil mining is allowed to continues. Unless we stop this TransCanada debacle, life as we and all other creatures of this earth will change to a point that we will wish we were dead. The sooner the humans are gone from the planet, the better for all other species. Hopefully, by then, there will still be some clean air and water and food to sustain them.


As usual, Joel Sartore's photographs enrich the information immeasurably. Wow.

I am wondering what the

I am wondering what the migratory patterns of birds can tell us about the history of the planet, its changing temperatures and its life span!

Unlocking migrations secrets

Working for a wildlife shelter it will be huge bonus when the price of these transistors make them usable by everyone not just the few who can get the funds to support their use. I would love to be able to track our releases as opposed to release and HOPE!


Although generally familiar with the idea of birds migrating, it took Scott Weidensaul's delineating it as "a new frontier" to really drive home to me the incredible flying and navigational feats of so many of our common birds, as well as the need to provide way stations, and protect their winter homes (March-April 2012). I am inspired to learn of ornithologists who are advancing knowledge of "migratory connectivity." We must do more to support these scientists and find ways to protect migrating birds who provide us with delightful sound and beauty, asking little in return. Marie Barry, Beverly, MA

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