KLEINFELTERSVILLE, Pa. - Thousands of snow geese soar upward in unison, swoop about, and land on snowy farm fields or the little patch of open water just thawed from the thick ice of a relentless winter.

Their cacophony of quacks and honks is punctuated by a burst of clicks from the long-lensed cameras of birders and nature lovers at the Middle Creek Wildlife Management Area in Lebanon County, operated by the Pennsylvania Game Commission.

"Here they come!" "Look, over there," exclaim 50 or so visitors at the observation point. The Pennsylvania acreage attracts a magnificent wildfowl show each year as the birds pause to roost while migrating thousands of miles north for nesting season.

On Saturday, the visitors craned their necks to see a group of hundreds of snow geese and tundra swans flying in formation.

The estimated snow goose count last Monday was 110,000, with 2,300 tundra swans and 1,800 Canada geese. By Thursday, the number of snow geese had dropped to about 65,000 as the birds make their way to their next roosting stop, the Finger Lakes of New York.

The teeming landscape of white swans and black-and-white snow geese was colored with smaller numbers of mallards, black ducks, pintails, wigeons, and ring-necked ducks.

Coming from as far away as northern North Carolina and headed up to northern Canada and northwestern Greenland, many of the geese will summer in Bylot Island in Baffin Bay.

"They breed 800 miles from the North Pole," said Al Keith, an attendant at the Middle Creek visitors center.

Pennsylvania's rolling farm fields are a perfect attraction for the birds. The reservoir at Middle Creek offers protection from predators at night and the agricultural fields, rich with winter wheat and other crops, supply the food they need to continue the migration.

"They need to have some snow-free fields to feed on, otherwise they would starve," said Keith.

Birders, photographers, families, and hunters - undaunted by Friday's spring snow and the departure of thousands of birds - came from all over to see the popular bird show: Pennsylvania, New Jersey, Maryland, West Virginia, New York, even California.

"There is a nesting ground by the Porta Potty," Olivia Grace, 7, said to everyone she passed on the Willow Point Trail. Her sister, Lilyana, 5, and grandmother Janet Kline, of Hummelstown, are big "animal fans," Olivia added.

"Morning and evenings are the best time to see birds on the lake," said Mike Epler, 51, a birder from Middletown in Dauphin County. He came equipped with a spotting scope, hoping to catch a glimpse of a Eurasian wigeon, a type of duck reportedly seen in the area.

It is the greater snow goose that birders are watching along the East Coast. The lesser snow goose migrates through the Western states.

Biologists are concerned about the environmental damage to the delicate arctic tundra done by the overpopulation of both species.

With their heavy feeding, the five million lesser geese are "ruining breeding grounds in north-central Canada," said Keith. "There are places out there that won't grow back in 100 years."

There were fewer than 50,000 greater snow geese in the late 1960s, according to the U.S. Fish and Wildlife Service. Now, there are more than a million, said Keith.

The flocks didn't always stop at Middle Creek.

It wasn't until 1993, with their numbers on the increase - warmer conditions have increased the survival of goslings - that the snow geese began to change course from their traditional coastal route, said Keith.

"Out of necessity, they have to come inland to find food," he said. Plentiful farm fields provide food for the increasing population that the old route could not sustain, he said.

Though the birds damage crops, farmers gain by leasing their land to hunters, said Keith.

Steve and Dave Feathers, a father-son duo from Hummelstown, were cruising the visitors center before heading out to a more secluded area on state land to hunt.

"We are into population control," said Steve Feathers, 58. "We just want to do our part."

The camouflage-clad pair looked the part of serious sportsmen but spoke more like master chef Gordon Ramsay as they described a meal they were planning: snow goose pan-seared skin-side down in a little butter with scallions, served with couscous and steamed or mashed squash on the side.

"They are so tasty," said Steve Feathers.

mschaefer@phillynews.com

610-313-8111

@MariSchaefer