Among the nation's 1,265 endangered or threatened species, there are flies that whir among California sand dunes, geese that inhabit Hawaiian mountain slopes and a tiny fish found in a single pond in Nevada.

But only three have this distinction: The District of Columbia is listed as their home.

Two of the three species -- the bald eagle and a tiny crustacean called the Hay's Spring amphipod -- can be found in the District, according to the U.S. Fish and Wildlife Service, which determines the list of endangered and threatened animals.

The third, the eastern cougar, hasn't been sighted in the District in two centuries, scientists say, and is believed to be extinct. But the big cat has found a niche in Washington's most labyrinthine wilderness, the federal bureaucracy. To the Fish and Wildlife Service, it remains endangered here.

The District's quirky threesome soon might be reduced to two if scientists decide that bald eagle populations have grown to the point that they can no longer be considered threatened. For the moment, though, the trio represents a microcosm of the nation's endangered species: Washington has a glamorous one, a gross one and a ghost.

The eagle, of course, is the glamourpuss. The birds lived in Washington until the late 1940s, then left a nest over the Anacostia River because of pollution in the water, said Craig Koppie, an eagle specialist with the Fish and Wildlife Service.

"The fish all died, so they couldn't feed their young," said Bob Nixon, chairman of the board of the Earth Conservation Corps. The group, which works to improve the Anacostia River and draws volunteers from city neighborhoods, began bringing young eagles from Wisconsin to the District in 1995.

In 2000, a pair of eagles settled into an 80-foot-high nest in an Anacostia oak. The spot is good for birds -- it's close to fishing grounds on both the Anacostia and Potomac rivers -- but it makes for an incongruous picture. The nest overlooks St. Elizabeths Hospital, Ballou Senior High School and the D.C. Council campaign office of Marion Barry.

"That was amazing to me that the eagle was nesting right there," said Twan Woods, 28, a Southeast Washington native who monitored the birds this year for the conservation corps.

Eagle watchers are hopeful that more will come soon. Nixon noted that osprey are recolonizing the Anacostia River, and he said there were reports of eagles casing Kingman Island there. "I think there's another pair that's looking to set up shop upstream," he said.

The bald eagle was put on the federal endangered species list in 1967, but it has rebounded well across the country and is now listed as "threatened."

Fish and Wildlife officials say they soon might take the eagle off the national list. While it would lose the status of a threatened species, which carries prohibitions on capturing the animal or destroying its habitat, scientists say the bald eagle still would have some federal protection.

It's harder to measure the progress of the Hay's Spring amphipod -- an eyeless white crustacean whose only habitats in the world are in the District, scientists say.

The amphipod, which usually grows to a quarter- or a half-inch long, resembles a tiny shrimp with legs like dental floss. It lives in six seeps, or oozy springs, in Rock Creek Park and on the grounds of the National Zoo.

It stays mostly in groundwater and the mud around the seep, eating bacteria and fungi on decaying leaves. For the scientists who search for the Hay's Spring amphipod, the hunt requires patience, luck and a willingness to turn over leaves for several hours at a time.

"You pray a lot that you're going to get a good day," said David Culver, an American University professor who is a leading authority on the amphipod.

Such endangered species as the amphipod that are found in only one spot are called "narrow endemics." Other examples include the Devil's Hole pupfish in the Nevada pond, and the Delhi Sands flower-loving fly, which lives on a smattering of sand dunes outside Los Angeles.

Critics of the federal endangered species program say such species have a disadvantage if they're pitted against a marquee animal, such as the bald eagle, grizzly bear or California condor, for funding and scientists' time.

"The amphipod, and obscure invertebrates and obscure plants . . . the justification to save those is the justification on principle" -- that every species is worth saving, said Tim W. Clark, a Yale University professor who studies endangered species policy.

"Where if you say, 'Let's go save the eagle,' " Clark said, "you don't have to explain all that. People say, 'Let's go do it.' "

The eastern cougar used to live in the District, scientist say, along with the buffalo, elk, wolf and black bear. If it hadn't disappeared from the area a couple of centuries ago, the big cat would be as hard to ignore as the eagle.

This subspecies, related to both cougars in the western United States and the endangered Florida panther, once was prevalent east of the Mississippi River. But it was decimated by hundreds of years of hunting and deforestation.

When the first endangered species list was being prepared in the 1960s, there was doubt about the eastern cougar's survival, and it was listed as endangered. Now, scientists believe the subspecies died out completely in the early 1900s, said Paul Nickerson, the recently retired chief of endangered species for the Fish and Wildlife Service's northeast region.

Other extinct species have been taken off the endangered species list. So why not the eastern cougar?

"We pondered trying to do that, but the problem with that is we got so many quote-unquote cougar sightings that taking it off the endangered species list would be an administrative nightmare," Nickerson said.

At last count, about 3 percent of all species on the endangered list also are considered "possibly extinct." The list includes the ivory-billed woodpecker in the Southeast and the Kauai 'O'o, a Hawaiian bird.

"Some species are still on the list because we only have so many people on staff," said Cindy Hoffman, a spokeswoman for the Fish and Wildlife Service.

The District government keeps its own list of endangered species, which includes the Atlantic sturgeon. This fish is believed to be gone from city rivers, but it has hope. Sturgeons remain in the Chesapeake Bay, and city officials believe they could return to the District eventually.

As for the eastern cougar, there are some true believers who have catalogued apparent sightings in the eastern United States, rather like Bigfoot fanatics. But even they don't believe the big cat is in the District.

"Oh, absolutely not," said Mark Dowling of the Eastern Cougar Network.

Still, most conservation experts say there's not much harm in leaving them on the list.

"If they are still out there, certainly you want to protect them," said John Kostyack, senior counsel for the National Wildlife Federation.

Bald eagles, such as the one pictured, have been spotted in recent years on Rosilie Island near the Maryland shore. Others have been seen nesting by the Anacostia River.