They are symbols of courage, freedom, power, and immortality.
Grim-visaged, they stared from Persian battle ensigns, decorated Greek coins, and perched amid Egyptian hieroglyphics.
For lovers of ''The Muppet Show'' they are personified by a crotchety and disapproving character called Sam.
Eagles, or more precisely the bald variety, have good reason to throw out their chests with pride this year: Not only are they being nationally honored, but they also appear to have been saved for succeeding generations.
President Reagan has declared 1982 the ''Bicentennial Year of the American Bald Eagle'' and June 20 ''National Bald Eagle Day,'' for which the proud predators might consider laying in a chunk of celebratory salmon. On that date in 1782 the Continental Congress decreed that the bald eagle would henceforth be the nation's symbol and national bird.
''Its presence on the Great Seal of the United States,'' declared President Reagan in a sonorous proclamation Jan. 29, ''one talon extending the olive branch of peace, the other brandishing the arrows of defense, is a symbol of friendship and cooperation to our allies and a warning to our adversaries that we are not to be trod on.''
To catch a glimpse of the magnificent bald eagle, the President went on, is to understand why the Founding Fathers chose it as a national symbol. ''Its grace and power in flight, its vigilance and loyalty in defending its family group, and, most of all, its courage make the eagle a proud and appropriate symbol for the United States.''
But what evokes the President's admiration today earned only scorn from Benjamin Franklin in 1784. He considered the bald eagle ''of bad moral character'' because it robbed the ''fishing hawk'' of its catch. He heartily disapproved of its selection as ''the representative of our country.''
As far as Ben Franklin was concerned, the wild turkey was ''much more respectable'' and ''withal a true original native of America,'' though he did admit it was ''a little vain and silly.''
It was on July 4, 1776, after the Declaration of Independence had been adopted, that the Second Continental Congress appointed a committee composed of Ben Franklin, John Adams, and Thomas Jefferson to produce a design for a national seal.
The initial proposal, the work of a Frenchman living in Philadelphia, featured a double-headed eagle along with the coats of arms of England, Scotland , Ireland, France, and Germany. It left Congress cold.
A second design, proposed by a second committee in May 1780 and dominated by a shield with 13 diagonal stripes, fared no better. A third, proposed by yet another committee, depicted an American soldier and a woman holding a dove. It, too, failed to generate much enthusiasm.
Charles Thomson, secretary of Congress, was then asked to make his own recommendation for the seal's design. As a central motif, he proposed a bald eagle, with a sheaf of -arrows in its right talon and an olive branch in its left. With certain alterations by William Barton, an artist and student of heraldry, the design passed Congress on June 20, 1782.
Mounted on the national seal, the majestic raptor (bird of prey) with its snowy head, hooked bill, and transfixing glare enjoyed total safety. In the wild , however, particularly as the 20th century advanced, it has been decimated by pesticides, shooting, and an inexorable loss of habitat.
''Ten years ago the bald eagle faced extinction in the lower 48 states,'' says Jay D. Hair, executive vice-president of the National Wildlife Federation (NWF). If its plight has considerably eased, as Mr. Hair claims, ''due to increased public awareness and the determined efforts of conservationists,'' the battle to ensure the survival of substantial numbers of bald eagles is by no means over, experts warn.
Centuries ago there may have been as many as 75,000 to 100,000 bald eagles wheeling above that part of the continent which was to become the United States. In 1976 the NWF counted some 3,000 bald eagles in the lower 48 states. In January 1981 it claimed this number had jumped to 13,709.
William S. Clark of the NWF's Raptor Information Center in Vienna, Va., estimates that about 70 percent of the birds were migrants from Canada and Alaska who had flown south in search of food. The contiguous 48 states have a population of some 4,500 bald eagles, he says.
But according to Dr. Jay Sheppard, an ornithologist with the US Fish and Wildlife Service, counting bald eagles is far from an exact science. ''It's rather like doing a count of (people in) Central Park on a hot day and saying that's the population of New York,'' he says. In his opinion, thousands of bald eagles go uncounted. But he believes there are probably no more than 1,400 breeding pairs in the lower 48 states.
The Department of the Interior still considers bald eagles ''endangered'' in 43 of the 48 contiguous states, a designation that indicates a threat of extinction hangs over them. The eagle is described as ''threatened,'' or likely to become endangered in Wisconsin, Minnesota, Michigan, Oregon, and Washington, according to the Interior Department. Bald eagles flourish in Alaska, where there are thought to be some 30,000 birds.
Found throughout North America near rivers, lakes, marshes, and estuaries, bald eagles feed largely on fish such as salmon, lake trout, carp, and bass. The salmon it devours have usually expired after spawning or are on the point of doing so. Bald eagles also prey on small mammals and birds such as rabbits, mice , coots, and grebes. Lazy eaters, they specialize in devouring injured or ailing waterfowl.
Bald eagles are by no means averse to grabbing their lunch from others. When Baron von Graffrenredck was exploring the Potomac in 1712, one of the most memorable sights he chanced on was a bald eagle attempting to relieve an osprey of the silvery repast writhing in its talons. The bald eagle's technique, apparently, is to so disconcert a victim with its harsh cackle that it drops its fish.
Growing to a length of 31/2 feet, with a wingspan of between six and eight feet and weighing up to 14 pounds, bald eagles nest, for the most part, in the tops of tall trees. But their nests, which are built of sticks and lined with moss, pine needles, grass, and feathers, can also be found on rock ledges and promontories.Pairs, who mate for life, are compulsive nest builders, adding fresh sticks to the aerie each year. One bald eagle's nest near Vermilion, Ohio, was 12 feet deep, 8 feet across and 36 years old.
Though of undeniable grandeur, the bald eagle has suffered severely at the hands of man.
Incredibly, they are still shot at. ''For a lot of people they are something to sight your rifle on,'' says Brian Millsap, a raptor biologist at the NWS Raptor Information Center, ''something to watch fall out of the sky.'' Although the birds are shielded by the Bald Eagle Protection Act of 1940 and the Endangered Species Act of 1973, the former imposing a year in prison or a $5,000 fine or both as the maximum penalty for those who shoot them, shooting is ''still a big problem,'' says Mr. Millsap.''
I call them vandal shootings,'' says Frank Kenney, a spokesman for the US Fish and Wildlife Service. ''There's a terrible prejudice against all predators.''
Federal and state wildlife agents last July arrested 16 people in Bellingham, Wash., for killing eagles, mostly bald eagles. In 1971, helicopter-borne gunmen massacred some 750 bald and golden eagles in southeast Wyoming.
Catching those who turn their guns on bald eagles is often next to impossible. ''They shoot and they're gone,'' says Frank Kenney.
The bald eagle, experts say, has been a sorely misunderstood bird. Its fierce appearance, emphasized by its bright yellow eyes, feet and bill, belie both its character and capabilities, they say. They insist it never has been able to snatch up deer, calves, pigs, goats, and babies, as popular folklore suggests.
On Sept. 23, 1929, in a story datelined Somerset, Ky., the New York Herald Tribune reported that an eight-year-old boy named George Meece, weighing 50 pounds, had been seized by a bald eagle weighing six to 12 pounds and hauled 20 feet into the air. By another account young Meece was elevated 75 feet and transported 200 feet away.
''Absolutely impossible,'' harrumphs Frank Kenney, who is a wildlife biologist. Bald eagles, he insists, can barely lift five pounds.
In Alaska earlier this century, misconceptions about the bald eagle cost thousands of birds their lives. Because they were thought, quite incorrectly, to be ravaging the salmon fisheries and to a lesser extent the herring and blue fox population, the territory of Alaska paid out some $100,000 in bounties for dead eagles between 1917 and 1953 when the practice was abandoned. The payments are thought to have resulted in the deaths of 125,000 to 128,000 birds.
The bald eagle's reputation for ferocity and appetite, largely undeserved, has cost it dearly. ''We've got a long way to go to educate people not to shoot bald eagles,'' says National Audubon Society spokesman Bob Boardman.
Pesticides such as DDT and dieldrin have played havoc with the majestic predators. Seeping into rivers, lakes, and estuaries, the chemicals are absorbed by water plants and animal organisms which fish and wildfowl feed on. The eagles then eat the contaminated fish and fowl with devastating results.
DDT, which was banned by the Environmental Protection Agency in 1972, caused the female eagle to lay eggs with shells so thin that they broke during incubation.
The banning of such insecticides as DDT and dieldrin in the early 1970s has meant that pairs of bald eagles that once produced calcium-deficient eggs or no eggs at all are now producing healthy eaglets. But the NWF's Brian Millsap says that although there are signs of improvement, ''DDT is still showing up in eggs. It's still causing problems.
''The destruction of the bald eagle's habitat has done much to thin its ranks. Nesting trees, in particular, have succumbed to agricultural, industrial, and residential development. ''The real threat is habitat loss,'' says Jack Greene of the NWF. The loss of habitat has been particularly severe in the lower Great Lakes, New York, and New England.
The NWF has proclaimed 1982 the ''Year of the Eagle.'' Throughout the yearlong observance, says NWF's Jay Hair, ''the bald eagle will stand as a proud symbol of what we can do to aid endangered species - if we care enough.''