Hawks are hard to find, at most times and in most places, and when one is spotted it usually is wheeling so high and away that even experienced birdwatchers may argue over the species.

Therein lies the magic of Hawk Mountain Sanctuary at Kempton, Pa., where migrating hawks can be seen by the thousands every fall, sometimes thousands in a single day or hour. The hawks, eagles and falcons usually are close enough for easy identification and occasionally pass or hover a few yards away.

Before the sanctuary was established in 1934 the ridge was a scene of slaughter. Gunners would congregate there to blast the hawks, which were despised as killers of chickens and game birds before it became generally understood taht they dine almost exclusively on small rodents and other "pests."

It is almost shocking to learn that Hawk Mountain is not, has not been and will not be subsidized by any government agency; it makes its way on admission fees ($1 adults, 50 cents children), memberships ($5 up) and donations.

A visit to the ridge is unforgettable, especially if you once happen to be there on such a day as the Thursday in late September when more than 21,000 broad-winged hawks passed. The view alone is worth the trip, which is an easy drive from Washington and from most of the other northeastern population centers. People who go there once go again and again, and they tell their friends and neighbors about it.

And therein lies the problem of Hawk Mountain. On nearly every fall weekend the 2,000-acre private sanctuary is so jammed with carloads of birders that the parking lots must be closed, and it may be a hike of three miles to the nearest parking place. The observation points along the ridge are packed with people cheek by jowl, which not only intrudes on the quality of the experience but tends to make the shy and secretive birds pass farther away or even cut across the ridge out of sight.

There will be no solution to the problem so long as there are those who love birds, and veterans come only on weekdays unless they're doing service as tally keepers. On most weekdays it's possible to find a good observation point so private that you can forget anyone else is on the mountain except when cheers go up for such rarities as bald and golden eagles and peregrines.

Part of the charm of the birds is their unpredictability. The classic "hot day" is overcast with a stiff wind from the northwest and bad weather over New England, but they're almost as likely to come swarming out of a clear blue sky.

When the birds come thick and fast the sanctuary staffers or volunteers may press casual visitors into covering a given sector of sky, but on most days, even at the height of the season, the birds come a few at a time and "only" dozens or hundreds on a given day. There is time to snack and nap, and when eyes and neck grow weary from scanning upwards you can search for deer in the meadow below.

There is friendly rivalry to be first to identify a distant bird, and everyone wants to be there on a record day. The sanctuary staff makes no claims of accuracy for the count, but it's safe to say that the totals represent only a fraction of the numbers that hitch-hike on the thermals along Kittatinny Ridge on their way to wintering grounds in the southern U.S. or northern Mexico.

Many other birds besides raptors pass by, including ponderous, croaking Vs of Canada geese.The ridge was raucous with bluejays one day last week, hundreds of them in a loose flock that was kept loose in part by the occasional depredations of a sharp-shinned or red-tailed hawk. A mourning dove made its way on foot along the path toward the sanctuary headquarters, certainly a sensible way for a predatee to cross Hawk Mountain.

"Oh, the things you see here," said one staffer, a young man who can't remember when he didn't love birds. "Now and then a hawk will stoop on a bird right in front of you, or a marsh hawk will come along carrying a fish in its talons, snacking as he goes."

He logged the time as a black vulture cruised by. "I'm glad you like this place, and I know you'll be back, but I wish you wouldn't write about it."