While Scarlett sat on her new chick on a sunny ledge outside the 33rd floor of this city's tallest skyscraper, falcon experts, corporate soldiers, TV camera crews and future insurance salesmen crowded near the window wondering, "What will Ashley do?"

Earlier this morning, Scarlett's caretakers had replaced four medium-sized eggs, which Ashley had declined to fertilize, with the first of three chicks, or eyases, as baby peregrine falcons are called. There were two eyases still inside, peeping woefully from a tin canister, under a brown towel.

"Our big question is what happens when Ashley sees the baby," said John Barber, a 29-year-old data programmer who has been given leave from his duties at the United States Fidelity and Guaranty Co. to attend to Scarlett and her suitors when necessary. "He has three choices. One, he could help Scarlett feed it. Two, he could ignore it altogether. Three, he could come in and start munching."

Scarlett, a 2 1/2-pound peregrine falcon with black eyes, yellow beak and formidable talons, deserted the wilds of the Eastern Shore four years ago for an aerie high up on the headquarters of USF&G. Except for mysterious two-week absences at Christmastime, she has been there ever since, perched on a south-facing ledge with a panoramic view of the harbor and the city's pigeons.

Ashley, however, is the latest in a line of suitors introduced to Scarlett. Red Barron, Blue Meanie and Misha spurned Scarlett. Rhett, who took up with her, unfortunately died of poisoning after dining on too many strychnine-tainted pigeons.

Thanks to pesticides, peregrine falcons are listed as endangered species. The raptors, which can see three times as well as humans and can fly 175 miles an hour attacking prey, all but vanished from the eastern United States in the late 1950s. Since 1975, a nonprofit group called the Peregrine Falcon Fund has tried to reestablish the birds; 353 young falcons have been released along the Eastern Seaboard, mostly in wooded habitats. A few have been released in cities, but Scarlett is the only peregrine that seems to have truly found a niche in the city, and will put up with its hazards, which include glass windows, unpalatable pigeons and, of course, too much media exposure.

Even though USF&G's emblem since 1896 has been the eagle, the insurance company built a gravel-filled nest for Scarlett called a "scrape."

Barber, who has a zoology degree, has spent hours on company time fishing out fledgling falcons from air-conditioning grates, sweeping up the pigeon bones that land on the plaza below and, wearing gardening gloves, distributing quail meat.

Scarlett has raised 13 foster falcons, one of which was hit by a truck. With her foster broods in the past, she has either had no males to contend with, or Rhett, who arrived too late to fertilize her eggs. This mating season, Barber and researchers from Cornell University placed Ashley in a wooden cage on the ledge. After a period of acclimatization Ashley was released. Showing no interest in mating, he is hanging around the west side of the building, returning to the south just for meals.

If Ashley doesn't munch the eyases, lays off bad pigeons, and can adapt to the lights of TV cameras, researchers are hopeful that he will mature and help Scarlett raise peregrines of her own.