Originally created 03/15/03

Shorebirds' movements are studied



CUMBERLAND ISLAND, Ga. - A meticulous study of individual shorebird movements on Cumberland Island might help biologists develop programs that protect the animals in years to come.

A graduate student and three assistants, all from Canada, have been on the barrier island observing semipalmated plovers the past two months to determine their diets and how they are affected by humans and other animals.

As students watch the flocks through telescopes, they focus on one bird for five minutes. Each hop, peck, flap, walk and other movement is counted to determine the best way, place and time to protect shorebirds of all types, said Melissa Rose, a graduate student majoring in biology at Trent University in Southern Ontario.

Weather conditions and tide levels are recorded while researchers watch individual birds or entire flocks, Ms. Rose said.

Ms. Rose, who has returned to Cumberland Island three consecutive winters to watch the birds, said little research has been done with migratory shorebirds in wintering sites.

Her observations have determined that many species of shorebirds - gulls, plovers, oystercatchers and others - congregate in what Ms. Rose describes as a mixed flock. Some mixed flocks on the island are as large as 4,000 birds, she said.

Individual species in the mixed flocks still congregate in groups, but Ms. Rose said it's likely the different species stay close to one another for mutual protection from predators such as hawks and falcons.

Ms. Rose said the birds gather in different areas on the island, depending on weather conditions. During inclement weather, shorebirds gather at the south end of the island along the beach when prevailing winds are from the west. The birds move to the west side of the island along the Intracoastal Waterway when the winds are from the east.

The researchers have been trying, unsuccessfully, to capture plovers to band for future research. Banded birds tell researchers about their migratory habits, feeding habits and life span, Ms. Rose said.

But the bird's eyes are so good that they avoid the traps' netting.

"We haven't caught anything yet," Ms. Rose said. "It's very frustrating."

John Fry, the resource management specialist on the island, said Cumberland Island's pristine habitat makes it an ideal place to conduct shorebird research.

"This could help protect these birds in the future," Mr. Fry said. "It could have some bearing on the way we manage the habitat."