Birds and their ancestors have been taking wing for more than 100 million years.

Humans are just now rounding out their first century of flight.

But increasingly, the flying machines that evolved from Wilbur and Orville Wright's 1903 miracle at Kitty Hawk find themselves in potentially deadly conflict with birds. More than 2,000 times a year in this country, an airplane smacks into a bird -- or a flock of them.

A runway at Elmendorf Air Force Base in Anchorage, Alaska, was littered with debris after an E-3 AWACS jet collided with more than 30 geese on Sept. 22, 1995, causing the aircraft to crash shortly after takeoff. All 24 members of the crew died in the accident.

With air fares at historically low levels and air travel burgeoning, collisions are on the increase.

The Federal Aviation Administration's solution: Make it less comfy for birds around airports.

The agency is proposing that the federal government try to quash attempts to improve marshy areas within five miles of airports.

Such environmental-enhancement projects are required under federal law when developers pave over wetlands -- this includes airports when they expand.

In many cities, these marshy areas near airports offer some of the best real estate in town for birds and other wild animals.

Some conservationists are fighting the FAA's plan.

The Bird Strike Committee, a group of government and industry officials, calculates a one-in-four chance that such an accident will cause someone to die in a jetliner crash in the next decade.

Environmentalists point out that such accidents are extremely uncommon.

By the Bird Strike Committee's count, 19 "significant" bird-plane collisions have involved large aircraft worldwide since 1960.

In nine occurrences, at least one passenger or crew member died.

The count does not include accidents involving small private planes.

Across the country, the feathers are flying in a flurry of bird-plane face-offs.

In Miami, federal officials proposed shooting white ibises, a bird cherished as the University of Miami mascot, whose numbers have dwindled 80 percent in South Florida.

In Seattle, controversy erupted over plans to build a new runway through a 20-acre patch of wildlife-sheltering wetlands.

In Anchorage, an effort to preserve lakes near the airport ran afoul of desires to ensure trouble-free takeoffs and landings.

And at New York's John F. Kennedy International Airport, where an Air France Concorde sustained more than $5 million in damages after hitting geese, thousands of birds have been shot right at the edge of a wildlife refuge.

The biggest danger -- for people, anyway -- is birds getting sucked into jet engines, causing them to fail.

Next most threatening: A turkey vulture or some other large-winged creature crashing into the cockpit during landing or take-off.

"Birds are an ever-present potential problem. The operative word here is potential," said Don Koorse, a Continental pilot who lives in Lake Worth but flies out of Newark, N.J., where the airport sits alongside a swampy area near Newark Bay.

Koorse said his closest call involved a collision with a huge white owl near McGuire Air Force Base in New Jersey.

"You could stall the engine out completely if there's enough feathers and meat going through the front of that engine,"Koorse said.

The FAA's solution has sparked cries of distress from conservationists.

"We're concerned about this idea that birds are 'in the way,'" said Gerald Winegrad of the American Bird Conservancy. "The FAA doesn't do birds. They do planes and plane safety, so the birds are just a pain in the butt to them."

"They say there are too many ducks and too many geese. I think there's too many planes," said George Matz, president of the Anchorage, Alaska, Audubon Society, who is spearheading the conservationists' fight against the FAA plan.

The FAA says it is only seeking to minimize the risk of deadly collisions.

"The FAA has ecological, as well as aviation concerns," Ed Melisky, the FAA's point man on the issue, wrote to Matz of the Audubon Society.

"It must balance these concerns to accomplish its mission of providing safe, efficient transportation throughout the United States in an environmentally sound manner."

Figures from 1997, the latest compiled, show 2,843 reports of planes hitting birds, up nearly 50 percent since 1990.

However, the incidence of serious damage is minimal: Of the 2,843 bird-aircraft mishaps reported in 1997, the windshields of 40 planes were damaged, and 140 planes sustained engine damage. Compare this with the average number of commercial airline flights each day: 34,853, on average, in 1997.

Five mishaps involving large commercial jetliners and birds have been recorded, worldwide, since 1975.

One was in the United States: at JFK in New York in 1975. None of the 139 people aboard was hurt.

But such accidents can be fatal.

The first man to fly across the United States, Calbraith Rodgers, also was the first person killed in an aircraft-bird collision in 1912.

The pilot of a Lear jet was killed in 1981 when a loon barreled through his windshield at 4,000 feet over Cincinnati.

And 24 people perished in 1995 when four Canadian geese flew into the engines of a U.S. Air Force AWACS plane at Elmendorf Air Force Base in Alaska.

Even if serious bird strikes are relatively infrequent, they can be expensive.

The total known damage to U.S. aircraft from 1991 to 1997 was $47.91 million.

The most strikes occur in California, followed by Texas, Florida, New York and Illinois.

Airports tend to attract birds because many offer the basics of life: Water in drainage ponds, food in the form of insects in grassy areas and protection from predators.

Many airports are in or near marshy areas.

There's a good reason: Towns were started on high, dry ground.

Airports came later and were often built where no one lived.

Some local examples: Miami International, in former Everglades; Fort Lauderdale/Hollywood, near the largest remaining stand of coastal mangroves in Southeast Florida; Homestead Air Reserve Base, near the Everglades.

Some of the nation's largest airports are alongside major bodies of water that attract birds, including San Francisco International; San Diego International; Laguardia and JFK in New York; and Washington National.

The location of these and other airports around swampy, low-lying tracts is doubly inconvenient, because it is there that many governments have chosen to locate garbage dumps.

They, too, attract birds. When developers or other builders -- including airport officials -- pave over wetlands, the law requires them to make up for environmental damage.

Typically, they must enhance other wild areas nearby.

For example, they might rehydrate an overdrained wetland.

The FAA's proposal would try to stop this work across a wide swath of South Florida, where civilization is wedged between the Atlantic and the Everglades and pockmarked with airports.

If the projects were disallowed in the five-mile radiuses, "Where would you put them?" wondered John Neuharth, spokesman for the South Florida Water Management District.

States where the most bird-plane collisions occur also have suffered some of the largest losses of wildlife-nourishing wetlands. Florida has lost the most: 10 million acres. More than 90 percent of California's wetlands are gone. In Texas, it's over half.

Over the years, airport workers have tried to ground the bird problem through a variety of methods, with decidedly mixed success.

They include firecrackers and other explosives; chemical repellants; pre-recorded bird distress calls; variations on the scarecrow theme, such as fake hawks and owls; and destroying the birds' eggs and nests.

New approaches are emerging.

At New York's JFK, airport workers have hired falconers, who send their falcons to disperse laughing gulls, swallows, egrets and other birds.

They are attracted by the Jamaica Bay National Wildlife Refuge next door.

At Southwest Florida International Airport near Fort Myers, an experiment is about to get under way. It involves a dog named Jet.

Jet is a border collie, a herding dog bred to run.

His former owners said he didn't make a good pet. So Jet was specially trained to herd birds away from airports, and next month, he begins his new job.

"We're always on the lookout for things that can make the environment safer," said airport spokeswoman Susan Sanders, "and we hope Jet will do that."