Researchers from the College of William and Mary’s Center for
Conservation Biology and The Nature Conservancy have observed the
record-setting migration of a shorebird from feeding grounds on the
Delmarva Peninsula to breeding grounds on the McKenzie River near the
The bird’s six-day flight is challenging conventional scientific thinking about long-distance migration routes and underscores the ecological importance of areas of the Delmarva Peninsula, which includes the state of Delaware and the Eastern Shore of Maryland and Virginia.
The bird, a female whimbrel known as
Winnie, was fitted with a state-of-the-art satellite tracking device
weighing just over a third of an ounce, according to Bryan Watts,
director of the Center for Conservation Biology. Winnie left the study
area on May 23, flying northwest at an average flight speed of nearly
22 miles per hour, covering more than 5,000 kilometers (3,200 miles) in
no more than 146 hours.
“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,” Watts said. “The flight documented this spring challenges some long-held assumptions and raises several new questions about whimbrel ecology.”
Watts and Barry Truitt, chief conservation scientist at The
Nature Conservancy, have been studying the importance of the rich
feeding grounds of the Delmarva Peninsula to whimbrels and similar
shorebirds, which winter in Central and South America. The birds stop
over on the Eastern Shore to feed on abundant fiddler crabs before
continuing their long journey to their northern breeding grounds.
There are two distinct populations of whimbrels, Watts said, a western group breeding in Alaska and the Northwest Territories of Canada and an eastern population, which breeds south and west of Hudson Bay in Manitoba and Ontario. He said scientists had believed that the western birds followed a Pacific coast migration, while the eastern population migrated along the Atlantic shoreline. Both populations are experiencing a decline in numbers, Watts added.
Winnie surprised scientists by making a transcontinental flight, northwest toward Alaska, rather than taking the route expected for a bird belonging to the eastern population of whimbrels.
The seaside of the Delmarva Peninsula has been recognized as a globally important bird area, a hemispheric shorebird reserve and a UNESCO biosphere reserve. Watts said Winnie’s flight shows at least some of the birds are migrating much longer distances than scientists had thought, a revelation that highlights the area’s value as a feeding station between the birds’ tropical wintering grounds and their Canadian breeding areas.
“The discovery that whimbrels use the site as a terminal staging area before embarking on a transcontinental flight suggests that the site is uniquely suited to provide the tremendous amount of energy required to prepare birds for such a flight,” he said.
In addition to setting a distance record, the bird bearing the tracking device also set a record for size, weighing 640 grams (1.4 pounds), which Watts said is 40 percent more than any other whimbrel recorded.