Eagle scouts help keep track of America's national symbol.

Byline: Scott Maben The Register-Guard

CORRECTION (ran 1/13/04): Bill Dingle's name was misspelled in a story on Page B1 on Saturday about a bald eagle survey.

HARRISBURG - The snow and ice retreated just in time for this week's winter bald eagle count in the southern Willamette Valley, but then the fog rolled in, obscuring views of the birds as they soared between roosts and feeding grounds.

Federal scientists and volunteers still caught glimpses of a few eagles to log in the annual survey, a tool for tracking population trends for the threatened species. The eagle, the nation's symbol for 202 years, continues to rebound after the government banned the pesticide DDT in 1972.

Hundreds of bald eagles are in Oregon now as migrating juveniles and adults mingle with populations that are mostly stationary year-round. Much more a scavenger than predator, the eagle follows its food, primarily dead and stillborn sheep in local pastures.

"They're very nomadic in winter depending on food sources," said Paula Larson, a Eugene-based wildlife biologist with the U.S. Bureau of Land Management. "They'll meander depending on the weather and the food supply and do what's energetically most beneficial to them."

Larson and volunteer Bill Bingle, a retired BLM engineer from Springfield, went looking for eagles Thursday and Friday in three areas: east of Harrisburg, southeast of Brownsville and along the McKenzie River.

They saw seven birds, down from last year's tally of 12. More eagles probably would have been apparent if not for foggy conditions, Larson said.

Roosts usually are a group of older trees that provide shelter at night. The eagles won't nest for another couple of months.

Late Thursday afternoon, about 10 miles north of Springfield, Larson and Bingle spent a couple of hours parked along Gap Road at the edge of a cold, muddy field.

"This really confines us, the ground fog," Bingle said.

Equipped with binoculars and a 60-power scope, they counted three eagles flying back to roost in the Coburg Hills.

"That's a little less than we typically do there," Larson said.

Even on on a clear day, the birds can be elusive, especially as only adults age 4 and older brandish the signature white head and tail feathers.

"They can be anywhere from 30 feet up to a little dot you can barely see," Larson said. "Sometimes, they'll fly right over top of you. It just depends where they're feeding."

A study in the early 1990s showed that the diet of bald eagles between Eugene and Brownsville was about 70 percent dead sheep and sheep afterbirth. Dead waterfowl and fish, however, make up the main course of eagles along the McKenzie and near area reservoirs.

The bald eagle, unique to North America, had declined throughout its range in the 1950s and '60s largely because of DDT residue in the fish that the birds ate. The contamination poisoned adults and resulted in thin eggshells that broke prematurely, killing the embryos.

Eagles also were shot or poisoned by ranchers who blamed the birds for killing lambs and other livestock, and some were poisoned after they fed on carcasses of coyotes and other predators baited by poison.

Some also succumb to power line electrocution, though that's far more rare today under new utility design standards.

Winter counts of bald eagles increased nearly 2 percent annually from 1986 to 2000, according to a U.S. Geological Survey analysis released last year. The analysis was based on 101,777 eagle sightings during 5,180 surveys in 42 states.

Numbers locally are relatively stable, improving some each year, Larson said. The Eugene BLM district tracks nine nests in the area, and more are probably out there, she said.

The National Wildlife Federation started the annual eagle survey in 1979, the year after the bird was listed under the Endangered Species Act as threatened in five states and endangered in 43.

The group sponsored the counts through 1991, then turned over the survey to federal scientists. In 1995, the bald eagle was reclassified as threatened in the contiguous 48 states.

Proposals to remove the bird from the list altogether are pending.

CAPTION(S):

A bald eagle spreads its wings to fly from its perch at Diamond Hill Road and Gap Road northeast of Eugene. Hundreds of the birds, both migrating and stationary populations, live in Oregon at this time of year. Paula Larson, a wildlife biologist with the U.S. Bureau of Land Management (left), and volunteer Bill Bingle, a retired BLM engineer from Springfield, count eagles along Gap Road.