Few customers of Fresh Market cast their eyes skyward as they enter and exit the Post Road East food store, focused instead on their shopping task and also because they wouldn't expect to find the natural drama playing out above the parking lot.

A pair of ospreys, or fish hawks, returned recently from their winter migration to the same nest they built last year and found at an acceptable home for their feathered family even though it is not in the exact same location. While they were gone, linesmen from Connecticut Light & Power moved their original nest -- built last year atop a utility pole along the busy route at the entrance to the Fresh Market parking lot -- to a platform on a 45-foot utility pole about 150 feet into the lot.

"Ospreys are very resilient and adaptive. Especially if successful with the previous nest they'll readily accept a nearby structure," said Milan Bull, senior director of science and conservation for the Connecticut Audubon Society.

Ospreys, one of North America's largest birds of prey with a wing span of up to six feet, are more often seen nesting in platforms above the marshes of Long Island Sound and other spots near the shoreline, but they are nesting in non-traditional sites because their numbers are growing, Bull said.

"It's an animal that's made a remarkable comeback," said Pete Fraboni, associate director of the Harbor Watch program for Earthplace nature center in Westport. Fraboni said the use of DDT and other pesticides in the 1950s and '60s endangered ospreys. Pesticides polluted waterways and the birds fed on contaminated fish that prevented their eggs from developing correctly. Thin egg shells could not support developing chicks.

Underscoring the birds' remarkable resurgence, Bull said Connecticut Audubon has identified more than 400 osprey nests in the state. Volunteers have been assigned to half of them for twice-weekly monitoring. He said the group is seeking another 200 volunteers to monitor the rest of the nests. They are also looking for information about other osprey nests that they may not be aware of. Monitors are given data sheets and record information used to track osprey productivity in the state. Bull said it's important to track the osprey population and success rate of nesting pairs, taking note of any dip in the numbers, which would indicate problems.

"Ospreys are a great litmus paper for the health and water quality of Long Island Sound. They don't feed on anything but live fish so they are good indicators of water quality and environmental health," Bull said.

DDT is no longer used but other chemicals, including flame retardants and pesticides, could show up in the water table and affect ospreys, which are at the top of the food chain and an important cog in that chain, Fraboni said.

Fraboni said the Westport shoppers are lucky to have a mating pair within easy viewing distance. They are lucky "to see a remarkable, majestic bird that was on the verge of extinction."

Ospreys will lay their eggs by the end of April. The raptors will sit on the eggs until they hatch about 29 days later. Then, about seven weeks after hatching, the fledglings will fly off.

For information about serving as a volunteer nest monitor visit www.ctaudubon.org and scroll down to Osprey Nation, a citizen scientist program in collaboration with the state Department of Energy and Environmental Protection. Green pins indicate those nests where monitors have been assigned; red pins mark those nests where monitors are needed.