Four gun-toting biologists scramble out of a helicopter on Southampton Island in northern Canada. Warily scanning the horizon for polar bears, they set off in hip waders across the tundra that stretches to the ice-choked coast of Hudson Bay.
Helicopter time runs at almost US$2,000 per hour, and the researchers have just 90 minutes on the ground to count shorebirds that have come to breed on the windswept barrens near the Arctic Circle. Travel is costly for the birds, too.
