MARGOT SINCLAIR played front-row volleyball at Ashley Hall and studied ornithology at Cornell. She spends her winters in Barbour coats and Bean boots, owns her father's Purdey shotgun, and can pole a boat over a marsh at flood tide when the clapper rails can be seen among theSpartina grass. Her grandparents were part of the Second Yankee Invasion of the South. Between roughly 1888 to 1940, Northern industrial wealth purchased vast tracts of worn-out cotton land, cut-over timberland, and abandoned rice fields. They restored old plantation houses or built new ones, and turned their estates into hunting preserves for duck, quail, turkey, and deer. The railroad brought resort towns to inehurst, Camden, Aiken, and Thomasville-golf, racehorses, polo, and quail. Each winter, the Sinclairs migrated from Tuxedo Park, New York, to Run-a-Gate Hall on the banks of the Cooper River above Charleston. Margot's father was born there as she was much later. She is so much a part of the Lowcountry that she considers herself a valid "ben-ya."