The new trail snaked through forested wetlands, then skirted a newly constructed rubble fill and circled a large marsh before abruptly ending in a stand of trees just short of the New York Avenue Bridge. This was a real treat, a new 1.5 mile section of a planned 60-mile hiker-biker trail connecting Maryland and the District of Columbia.

As we headed back to the marina, we focused more on the avian life and less on the amazing job planners had done in restoring 50 acres of wetlands and laying down a trail in a narrow bank of parkland between industrial operations and the river itself.

Sparrows were everywhere. Flocks of robins and cedar waxwings mobbed berry-laden bushes. A red-shouldered hawk flashed directly in front of us at one point. We saw wood warblers and a hairy woodpecker, too. Beavers had felled a number of trees.

We returned to the boardwalk, which stretched through the damp forest edge, elevated a few feet above the soggy soil. The tidal river was just 30 feet away. We spied three big black birds with long, narrow necks floating on the river. They were riding low in the water, with their long thin bills tilted up. The bird nearest to shore suddenly plunged out of sight, prompting the other birds to follow suit.

These diving birds were unmistakably double-crested cormorants (Phalacrocorax auritus). There are only seven long-necked, black diving bird species in the United States, and just one of them is seen here on the Anacostia River.

There is reason for concern about the population size and habitat loss for a number of the North American cormorant species. The opposite is true for the double-crested. The species has made a strong recovery in the last 50 years with the aid of a ban on the feather trade and the prohibition on deadly pesticides.

The bird is a generalist, comfortable in both fresh and saline waters. The double-cresteds are found along both coasts and the Gulf of Mexico, inland lakes and many river systems. The colony of double-crested cormorants on Poplar Island is enormous, with thousands of birds jamming this model Chesapeake island restoration project.

Double-crested cormorants have long, gooselike bodies with stiff tails and long, thin bills that end in hooks. Adults are black, and the sexes look alike. They have a yellow gular pouch, similar to the one seen in pelicans, but much smaller.

During the breeding season, adults can raise modest feathered crests on both sides of their heads. These eponymous crests are rarely seen, though, especially in the East where the crests tend to be black. Out West, some double-crested cormorants have white or speckled black-and-white crests, making them more visible.

Cormorants are fishing birds. Although the feathers closest to their bodies contain natural oils, their flight feathers do not. Without the extra buoyancy that the oil provides, these birds can compress their wings, squeezing out any air pockets, and dive under water for long periods. They catch small fish during these dives, but wait to eat them until they return to the surface. Cormorants swallow the fish whole, letting their digestive systems do all the work. Each morning, the cormorant will regurgitate an oblong pellet of indigestible fish bones and scales. Owls are noted for similar behavior.

The birds we saw diving into the murky waters of the Anacostia propelled themselves with strong kicks of their webbed feet. The lack of natural oil means the feathers will get saturated during repeated dives. After a period of fishing, the birds emerge from the river to fly up to any handy perch: a tree, a post, a bridge abutment or a communications tower. There, they will spread their wings, giving them a chance to dry in the sun and air.

While the birds may fish singly or in groups, they are a communal species. They roost together at night, often perched upright on their webbed feet, unlikely sentinels standing watch over the river or lake.

The birds are a common sight up and down the Anacostia. Double-crested cormorants are survivors, rebounding from hunting pressures and poisoned food webs.

The Anacostia, too, is rebounding from an even longer history of abuse and neglect. The well-maintained industrial yards bordering the new trail will have to continue managing their stormwater runoff, and watershed communities will need to make vast improvements in their control of sediment pollution. But these new wetlands will help, slowly cleansing the waters and providing excellent habitat for a multitude of birds, bugs and beavers.

As the cormorants on the river popped back into view, I realized that the right combination of hard work, thoughtful planning and steady effort can lead to rebirth and regeneration. And that is a future to be embraced both for ourselves and our river.