Endangered species are supposed to be hard to find, but there's a place within driving distance of Washington where two endangered species are thriving, along with a host of other intriguing birds and animals.

Blackwater Wildlife Refuge, a federal preserve near Cambridge on Maryland's Eastern Shore, is home to about 40 American bald eagles and more than 400 Delmarva fox squirrels, both of which are listed by the government as endangered.

On a decent day it's possible to see both, along with thousands of Canada geese and concentrations of snow geese, wild ducks, herons and other denizens of the marsh. The combination makes Blackwater a fine destination on a winter drive to the country.

The bald eagles have begun a comeback in the Chesapeake Bay region since almost being wiped out by widespread use of the pesticide DDT. After the poison was banned in 1972, eagle populations stabilized and recently the national bird has slowly begun to increase in numbers.

Today the Chesapeake region is one of four major bald eagle nesting and roosting areas in the lower 48 states, along with Florida, the Great Lakes and the Pacific Northwest. Dorchester County, where Blackwater is, claims the largest concentration of nesting bald eagles in the East, north of Florida.

This is courting season for the eagles and refuge manager John Schroer said the Blackwater birds are busy building at least two active nests. Last year six eaglets were hatched within the refuge.

When eagles are courting they often engage in a kind of airborne dance, swooping and dipping in pairs over the marshland. I was witness to such a courtship last month on a beaver pond on the lower Potomac, but my visit last weekend to Blackwater was not similarly blessed.

Schroer said the Blackwater eagles generally fly in the mornings and evenings. During the day they sometimes can be seen roosting in the tops of dead pine trees. Look for the mature eagles' distinctively snow white heads and tails, like a bird in a tuxedo (immature bald eagles are brown). The best days for eagle watching are sunny with little wind.

Sunny, still days are good for observing Delmarva fox squirrels, as well. These oversized bushytails are victims of declining habitat, and by far their greatest numbers are in and around the refuge. They favor mature forests of loblolly pines and hardwoods, rare outside of Dorchester County.

The woods of Blackwater are of that sort, giving them the eerie look of the Everglades, where tiny rises in elevation produce a landscape that shifts from water to marsh to hammocks of tall trees. Schroer said the woods were last lumbered here 70 to 90 years ago, and since then the fast-growing loblollies have shot up to scrape the sky, mixed in with tall hardwoods.

The result is an unusually high woods, where the canopy of treetops blocks out direct sun. It keeps the understory from growing into a tangle, so walking the forest trails at Blackwater is the easiest woods walking you'll ever find. All you have to dodge is giant tree trunks; the daylight filtering through the canopy dapples the ground.

Delmarva fox squirrels build their nests near the ends of the tree branches, unlike gray squirrels, which favor the crotch of a limb. The fox squirrels are slow moving and often will lumber away through the woods until they are out of sight, unlike gray squirrels, which head for the nearest tree.

A third endangered species, the red-cockaded woodpecker, is said to have used Blackwater, though this bird has not been seen since 1976.

Most people go to the refuge, a pleasant two-hour drive from Washington, to see the Canada geese. This year goose watching is something of a disappointment. During its heyday in the late 1960s, the 14,000-acre Blackwater was host to up to 100,000 Canadas during peak migration in November.

But lately the peaks have been in the 55,000 to 60,000 range. Refuge managers have changed tactics a little, providing less food for the migrants by changing farming policies on the tillable land. They began to fear that too many geese were resting there, raising the specter of a disease racing through the crowded flocks.

The peak concentrations were at the end of November this year, but there remain some 21,000 Canadas using the refuge, along with 7,000 wild ducks (half as many as last year) and about 3,000 snow geese. A drive around the five-mile wildlife loop provides plenty of views of waterfowl in their natural state, and there is an undeniable beauty in watching the sun set purple over the flat marshes as flocks of waterfowl cascade into the resting areas.

Elsewhere, tall great blue herons fish in the still ponds; deer pop out of the woods' edges and pop back in when they see people; swarms of blackbirds ebb and flow like giant, noisy clouds. Back at the park headquarters, children can take the simple wildlife tests and see, close up, what muskrats and eagles and nutria and Delmarva fox squirrels look like.

My wife demands a Blackwater visit once a year and evidently a lot of other folks do, too.

"We get a lot of people from Washington and Baltimore even in the spring, after the waterfowl have left," Schroer said. "It's just a place to see something natural, instead of street lamps and concrete."