Now that they spend more time in grain fields, their daily routine is more predictable, making them easier to hunt.

No one seems to know exactly why snow geese shifted their feeding patterns from salt marshes to crop fields, but somewhere back in the 1970s vast flocks of snow geese spent more and more time in corn, soybean and wheat throughout the region.

Most wintered on such refuges as Prime Hook in Delaware, Maryland's Blackwater, and Chincoteague, located on the Virginia/Maryland border, and fed on marsh grass in and around the refuges themselves. While many snows still use those havens as a home base of sorts, they have shifted their feeding patterns away from the salt marshes to grain fields.

"There were always a few that fed in agricultural fields, but that phenomenon really took off in the late '70s and '80s," says Virginia waterfowl biologist Gary Costanzo. "One theory is that farmers started working larger and larger fields, and that gave the snow geese the security they didn't have in smaller crop fields. They are able to feed farther away from hedge rows and trees in large fields."

Others cite the upward trend in the population as a whole as the primary reason the Atlantic Flyway snows started field-feeding. The high number of greater snow geese meant existing food sources were exhausted more quickly, leaving the geese little choice but to shift from marshes to grain fields.

The current population is estimated at somewhere under 1 million birds, up dramatically from just 30 years ago, but Costanzo says the nesting grounds of the greater snows is in much better shape than that of the lesser snows, found primarily in the Central and Mississippi flyways.

The problem with snows, Schrader quickly learned, is that they can be tough to pattern and even harder to decoy. Unlike Canada geese, which never seem to have a specific destination in mind and readily drop into a spread for a look, snows leave their nighttime roost and beeline for a specific feed field. While that may seem like an easy pattern and a slam-dunk hunting opportunity, it's not. In fact, Schrader says the key to success is a combination of ingredients.

"You have to be set up in the field they want to be in. You can put out 1,000 decoys in a field full of food, but if they don't want to come in, they won't," he says. "The best way to be in the right place at the right time is to watch the birds leave a specific field and be there the next morning. Wherever their feet leave at night is where I want to be the next morning."

Capt. Pete Wallace, a 30-year resident of Chincoteague, Virginia, guides for snows primarily on the salt marsh flats around the refuge. While Schrader hunts fields and ponds almost entirely, Wallace says access to the grain fields on Virginia's portion of the Delmarva Peninsula is difficult at best.

"They travel a hundred miles or more to feed every day. Snows tend to find a field and work on it for three days, maybe four, and once they leave, they don't come back--so you need access to lots of different fields to be successful," he says.

Wallace adds that the increasing population of white geese that use Chincoteague as their home base has actually made hunting them harder. More birds means larger flocks and more eyes studying a spread of decoys as they swirl overhead.

"All it takes is one out of 200 to see something it doesn't like and the whole flock is gone. You better have everything in order," says Wallace. "I only use shell and full-body decoys because rags and socks are useless."