Whimbrel Surprises Scientists with Coast to Coast Journey

The migration route of a whimbrel nicknamed "Winnie." © The Nature Conservancy

When The Nature Conservancy’s Barry Truitt and a crew from the Center for Conservation Biology equipped a whimbrel with a tiny satellite transmitter, they hoped to answer lingering questions about how this big shorebird migrates.

But because this whimbrel, nicknamed Winnie, flew to breeding grounds in Alaska instead of Hudson Bay in central Canada, the flight raises as many questions as it answers.

Just 13 days after Winnie – weighing in at more than a pound – took flight from the marshlands of the Conservancy’s Virginia Coast Reserve, it arrived on the coastal plain of Alaska’s Arctic National Wildlife Refuge. The refuge is part of the vast wildlife nursery profiled in the Conservancy’s Alaska-Yukon-Arctic Ecoregional Assessment.

Truitt, chief conservation scientist for the Conservancy’s Virginia Coastal Reserve Program, and biologist Bryan Watts, director of the Center for Conservation Biology at the College of William and Mary, have shown the reserve is a vital staging area for migrating whimbrels each spring. During these stopovers on the Delmarva Peninsula of Virginia’s Eastern Shore, the birds find strength for the journey in the form of fiddler crabs. With decurved bills that almost perfectly conform to the shape of the crab’s burrow, whimbrels such as Winnie gorge themselves to store up the fat reserves necessary for a marathon flight.

“We called it the ‘chicken whimbrel’ in the field as it was fat as an oven stuffer chicken at 640 grams. Fiddler crabs must be jet fuel!” said the Conservancy’s Barry Truitt. (Read a complete Q & A with Truitt.)

Data recorded with the help of the 9.5-gram, solar-powered satellite transmitter cast doubt on earlier assumptions about whimbrel migration and even whether North American subspecies exist. It also highlights the significance of East Coast habitats protected by the Conservancy. One of the Conservancy's initiatives promotes protection of critical habitats for migratory birds throughout the Western Hemisphere.

“This discovery sets a new distance record in the flight range of this species and highlights the hemispheric importance of the Delmarva Peninsula as a staging area for migratory shorebirds,” said Watts. “The flight documented this spring challenges some longheld assumptions and raises several new questions about whimbrel ecology.”

The continent’s whimbrel population is estimated at about 66,000, divided into two subspecies. The rufiventris subspecies of about 26,000 birds is thought to nest in Alaska and the Arctic coast. The Hudson Bay hudsonicus subspecies numbers about 40,000.

"Alaska’s Arctic coastal lands are highly important for migratory birds. The wetlands of the North Slope are alive in the summer with birds from all over the world that come here to raise their young," said Amalie Couvillion, the Conservancy's Arctic program manager in Alaska.

The flight reminds us of Alaska's link to the world, said Stan Senner, a biologist with Audubon Alaska. "To me, this once again is a tangible demonstration of how Alaska wild places are connected to people and places across the continent and around the world."