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.
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.