The world of Washington, with all its legal infighting and bureaucratic backstabbing, seems a million miles from the gentla marshes, wooded dunes and broad meadows here on the Texas coast.

Herons and pelicans feast on the small sea animals that live in tidal pools. Deer and wild turkey roam open grasslands, while the rufuge's inland ponds provide a home for alligators, turtles, frogs and an abundance of waterfowl.

But the special treasure of Aransas are the 78 whooping cranes that use its marshes and those on nearby Matagorda Island for their winter habitat. And because of those endangered cranes, this territory is in the middle of a bitter struggle involving Interior Secretary James G. Watt, environmentalists and Texas.

From faraway Washington, the fight sounds simple enough. Watt is considering the transfer of 18,992 acres on Matagorda Island to the state. Environmentalists say the move could turn Matagorda Island into another Coney Island and threaten the habitat of the whoopers and other endangered species.

But this struggle is no more simple than the delicate ecosystem at Aransas. The land in question is an old Air Force bombing range, and its status as part of the Aransas refuge is at issue legally.

The habitat of the cranes on Matagorda Island is already owned by Texas and a private individual. The Carter administration came close to giving more than half of the acreage to Texas in 1979. And the state says environmentalists' fears are unfounded because it has no plans to allow significant development of the island.

"There are a lot of people who think the federal government is about to give an island from the refuge system to the state," Texas Land Commissioner Bob Armstrong said. "It's much more sophisticated than that."

The Aransas National Wildlife Refuge was created in 1937 and encompasses 54,829 acres on Blackjack Peninsula, about 60 miles up the Texas coast from Corpus Christi.

Matagorda Island sits a few miles across San Antonio Bay from Blackjack Peninsula. It is a thin strip of land about 40 miles long. A Dallas oilman owns the bottom section, while the state owns marshlands on the inland, or bay, side as well as the beachfront on the Gulf of Mexico, according to David Dean, general counsel to Texas Gov. William Clements.

The remaining 18,992 acres is federal property. It was acquired by the Air Force during World War II and became the Matagorda Island Bombing Range. The service dropped lived bombs on the island until the fall of 1974, according to Maj. Lew Lambert of the Strategic Air Command.

The Air Force stopped using Matagorda as a practice range after environmentalists protested that swooping B52 bombers and rattling helicopter gunships had caused the population of the spectacular, 5-foot-tall cranes to decline.

The white-feathered cranes winter in the marshes on Blackjack Peninsula and Matagorda Island. Frank Johnson, the refuge manager, said 40 to 50 cranes use the Aransas refuge marshes, about 18 cranes winter on state-owned marshes on the island and the rest use marshes on private land on Matagorda or on a nearby island.

State and federal officials say no cranes have been sighted on the disputed federal land on Matagorda Island. Ned Fritz of the Texas Committee on Natural Resources says two cranes were sighted on the federal land this year.

On Nov. 20, 1971, the Air Force entered into an agreement with the Department of Interior in which the U.S. Fish and Wildlife Service agreed to advise the Air Force on wildlife management problems.

After the Air Force dropped the bombing range, which was also used as a recreation spot for officers, it was declared excess in 1975. The General Services Administration held title to the land and the Department of the Interior obtained the right to manage it.

Texas has wanted to manage the land since the Air Force declared it excess. In 1979, the Carter administration reached a tentative agreement with the state to turn over 11,000 acres at the north end of the island to the state. Texas' position was that it should receive all 19,000 acres and the deal was never consummated.

But last Jan. 2, outgoing Interior Secretary Cecil D. Andrus wrote Clements, "Our mutual objectives to maintain the natural character of Matagorda island seem to be entirely compatible."

When Watt told governors last winger he was willing to consider transferring federal land back to the states. Clements renewed the Texas request for the acreage on Matagorda Island, and when Interior officials announced they were seriously considering the request, the furor erupted.

On July 2, John Grandy, executive vice president of Defenders of Wildlife, sent an angry letter to Watt, saying "the disposal of Matagorda could seriously undermine the chances for survival" of whooping cranes and said removing federal lands from the refuge "would show a singular disregard for the public trust."

Fritz, citing a 1975 study by the Texas Parks and Wildlife Department, said the state would allow massive development on the island. He said the 1975 study called for a mass transit system on the island, parking spaces for 350 cars and various facilities for hunters, fishers and picnickers. "Eventually they would change Matagorda Island to Coney Island," he said in an interview.

The state sharply disputes Fritz's claims. The 1975 plan was prepared by a previous administration and is not under consideration now. Jon Ford, Clements' press secretary, said the plan "doesn't have anything at all to do with it. What we're talking about is very limited access to a small area. There's going to be no cars on the island."

The state would provide a small ferry to the island and would make the area available for primitive use, Ford said.

Even that much worries Grandy. "We have no assurance that if they start a small ferry and reasonably modest use now, in future years they will say they've changed their minds. They obviously want to do something on that land that isn't being done now."

Interior Assistant Secretary Ray Arnett visited the island earlier this month and met Clements to discuss the transfer. After the meeting, Clements said, "I don't know of any basic disagreement between us."

What is now being contemplated is a joint-management agreement in which Texas would take title to the land, but Interior would have a role in determining how it should be administered.

"We are committed to maintaining the integrity of the island," Dean said. "There will be no commercial development. Interior has been assured of that."

Arnett said he has seen nothing from Texas "that would indicate they would open it up in a way that threatens anything," adding that Interior has a responsibility to protect the whooping cranes no matter who owns the island.

Working out the details could take months, and the Defenders of Wildlife is prepared to block any transfer in court. "We're prepared to bring suit under the 1976 amendments to the National Wildlife Refuge System Administration Act, which prohibits removal of lands in a refuge system without express authorization of Congress," Grandy said.

Whether the land legally became part of the Wildlife Refuge is in dispute. Grandy, in his letter to Watt, said the 1971 cooperative agreement brought the land under the refuge system.

But the official Fish and Wildlife Service brochure issued at the refuge headquarters does not mention any of the land on Matagorda Island in defining the area of the refuge and a map accompanying the brochure does not outline any of the island.

And a Jan. 16, 1975, letter from then-Interior Secretary Rogers C. B. Morton to Sen. William Proxmire (D-Wis.) indicated the land was not then officially part of the National Wildlife Refuge system.

State officials seem confident they will receive the land, and the legislature has appropriated $250,000 a year to manage it. But the environmentalists are just as insistent they will prevail. "It's illegal," Fritz said. "The law prevents them from making the transfer."