There are electric days each fall, when a strong wind from the northwest has cleared rain clouds from the sky, when you can stand on a rocky outcrop of Hawk Mountain, high above a patchwork valley of Pennsylvania Dutch farms, and see eagles and hawks soar past in numbers too great to count.

Peregrine falcons, bald and golden eagles, red-tailed, broad-winged and sharp-shinned hawks, an average of more than 20,000 birds of prey move south each fall on winds that carry them over central Pennsylvania's Kittatinny Ridge. And every year, men and women wait on the ridge with binoculars and cameras to capture some of the raptorous glory of that flight.

"I've stood here on days when you couldn't see anything but hawks, from right in front of your eyes to the horizon 70 miles away," said Ron Jurgens, a retired steelworker from Pittsburgh who has made an annual fall pilgrimage to Hawk Mountain for 20 years. "I've been here days when you felt like you were holding your breath for six hours straight."

The annual migration of hawks always has drawn people to this mountain ridge. But until 1934, when Hawk Mountain became the first hawk sanctuary in the world, most visitors had a more lethal purpose than those who come today. Instead of cameras, they brought shotguns and used the magnificent birds for target practice.

An article in the Pottsville Journal in 1929, under the headline "Sportsmen Shoot Migrating Hawks," reported the sport of men who "almost daily congregated and poured many boxes of shells in the blackened skies, killing as many as eight with a single bullet."

The birds were not shot for meat or even feathers. Their carcasses were left to rot on the rocks. The unlucky ones, that were only wounded, died of hunger and thirst on the ridge slopes.

The massacre continued until 1934 when Rosalie Edge, who was called "the only honest, unselfish, indomitable hellcat in the history of conservation" by one of her friends and "a common scold" by some of her enemies, raised money to buy the mountain and protect the birds from the hunters she referred to as "barbarians." This week the sanctuary, which is four hours from Washington, celebrates its 50th anniversary.

To be fair to the hunters, most of them local farmers, hawks at that time were regarded as varmits that threatened chickens and small children. State game commissions encouraged their elimination, even offered bounties on certain species of hawk.

Edge and her supporters set about to change that image through education and lobbying. The Hawk Mountain Sanctuary Association opened the mountain to visitors and began conducting raptor workshops. Though the killing stopped on Hawk Mountain, it would be 40 years more before hawks were totally protected when the federal Migratory Bird Treaty Act was amended in 1972 to include all hawks and owls.

The decades of the 1960s and 1970s were both the best and worst of times for America's raptor species. Worst because of the alarming decline in such birds as bald eagles and peregrine falcons and best because the publicity accompanying that decline provoked new programs to aid all raptors. The pesticide DDT, which studies showed caused eagle eggs to break prematurely, was outlawed. Money was committed to the preservation of raptors, and not for entirely selfless reasons. Like the canaries coal miners once carried into mines, the demise of the hawk was evidence of a greater danger.

"Many people began to view hawks as a barometer of environmental quality. Hawks resided at the top of the food chain, occupying a position analogous to that of humans, and they quickly reflected the biological consequences of unseen chemical changes in our environment," wrote Paul Roberts, chairman of the Hawk Migration Association of North America, in the 50th anniversary issue of the Hawk Mountain News.

In recent years, most of the news regarding raptors has been good. The view from Hawk Mountain certainly reinforces that trend. In 1978, on one day in September, counters spotted 21,488 raptors. A year later, again in a single day, 2,616 sharp-shinned hawks were seen. This year there have been sightings of 30 bald eagles. Last week observers saw four bald eagles and 83 ospreys pass the ridge during one day.

Last week, standing on rocks that were once littered with spent shells and dead birds, a dozen of us watched the sky for migrating birds. Though strangers, we shared a comfortable camaraderie, exchanging bird stories until someone would call out a sighting. Immediately the binoculars would scan the sky for the osprey, kestrel or sharp-shin, soaring up to 40 miles an hour on southerly winds.

Though hardly the prettiest, one of the best fliers to pass the ridge was the turkey vulture. They are so good at finding wind, you will rarely see one flap a wing.

"I've heard a lot of people say if they could come back as a bird, it would be a turkey vulture," said Laurie Goodrich, a graduate of Woodward High School in Rockville, Md., who now works as a staff biologist at the sanctuary. This day she sat on the mountain with a clipboard, checking off the birds as they flew past. "They look like they're having so much fun."