It's dawn in a wetland along South Baltimore's industrial waterfront, and a mist is rising from Curtis Bay to reveal what looks like a wooded island populated by herons amid smokestacks and oil tanks.
A closer look reveals that the birds are nesting not on an island but on an overgrown shipwreck, one of more than a dozen cargo ships, passenger steamers, tugboats and barges - as well as a gambler's yacht - peering from the murk in this maritime graveyard.
Large wooden beams hewn to ply the Atlantic Ocean have sprouted marsh grass. Hulls have evolved into mossy lagoons ringed by trees and swarming with rockfish, shrimp, crabs, cormorants, swallows, cow-nosed rays and a few enterprising fishermen.
"It's serene and beautiful down here, and it feels like you're out in the middle of nature, even though there's industry all around," said Tom Michael, who fishes, camps and swims amid the wrecks in the shadow of a chemical factory and the Interstate 695 bridge.
"People say the water's dirty, but I think the fishing is better here than anywhere on the Eastern Shore," said Michael, 43, a motel manager from Glen Burnie, as a truck screamed by overhead and a great blue heron perched on a rusting barge.
Exploring Baltimore's 63 acres of tidal wetlands is like touring a post-industrial archaeology site that inexplicably doubles as a fertile breeding ground for fish and birds.
Although state environmental officials warn against eating catfish, eels and carp caught in the Patapsco River, after two centuries of being poisoned by industry, the city's wetlands are thriving and expanding.
The National Aquarium in Baltimore and Maryland Port Administration are planting several acres of marsh grasses, cleaning up debris and pollution, and planning nature trails, a public beach and a bird sanctuary.
Glenn Page, director of conservation at the National Aquarium, said researchers have documented 240 species of birds - including bald eagles, kestrels and hawks - in a 7.5-acre wetland planted recently in the city south of Fort McHenry.
"All wetlands are important, but particularly urban wetlands, because we've lost so many of them," Page said. "Marshes act as sponges to protect areas from flood damage during storms. And, even in cities, there is better water quality, aesthetics and fish reproduction when there are more wetlands."
The jumble of weedy wrecks that Michael enjoys fishing off in Curtis Bay include The Dover, The Ashland and the Fort Scott. They were part of an ill-fated fleet of nearly 1,000 wooden freight ships that the Navy commissioned during World War I. The ships were built so hastily - at a cost of hundreds of millions of dollars - that many leaked and were immediately scrapped.
Near their rotting shells, a pair of cow-nosed rays soar beneath the coffee-colored water. Diamond-shaped and about 4 feet wide, they lift the tips of their wings above the surface for a moment before plunging deep down and then resurfacing.
A cormorant perches in the pilothouse of a half-submerged tugboat, its waterline bearded with barnacles. On the stern of the decaying 1887-built sidewheel steamer Emma Giles - one of the most popular passenger ships in the city's history - somebody has spray-painted "Free to Good Home."
A family of ducks has accepted this offer, paddling in a sheltered pond inside the ship's skeleton.
About three miles north, near the Fairfield Auto Terminal, the Maryland Port Administration is planning to bury about 120 acres of waterfront, contaminated over decades by the ship-breaking industry, under tons of mud scooped from the bottom of the river, said Frank Hamons, a deputy director at the administration.
This will seal a polluted site where workers stumbled across a dozen inert World War II-era bombs last year. And in the adjacent Masonville Cove, the state is planning to plant wetlands and aquatic vegetation, build public hiking trails, a fishing pier, canoe launch, bird sanctuary and two beaches for fishing, Hamons said.
The cove lies across the Patapsco from Fort McHenry. It's surrounded by lush marsh grass and trees, but the waters are thick with brown seaweed, soda bottles and plastic foam cups.
Schools of tiny fish surge under the debris, leaping above the surface as a boat passes by. A rusting water tank fat as a submarine rests on shore, not far from a plastic dollhouse and a red-white-and-blue football washed up by a storm.
Around the corner, in an inlet, an abandoned passenger ferry, three stories tall and perhaps 150 feet long, with two stout smokestacks, tilts at a crazy angle, its windows shattered. Inside, swallows have nested behind the bar in a ballroom with paint curling off the walls in leafy flakes.
The birds burst out of their hiding places, flying in circles around the inside of the wreck and chirping furiously when someone approaches.