On an otherwise calm and still morning, when the chink of hardware and the grunts of his own exertions are the only sounds to assail a climber's ears, a great wind may suddenly well up overhead, transfix him to the rock and, in the wink of an eye, disappear. It is as though sonle unseen force had thrust through the atmosphere and a small measure of sky had been abruptly sucked out of existence. A slight quivering of air and flesh may linger for some moments after the reality has passed. The event, of course, has marked the swift and sure stoop of the peregrine falcon along the cliff face, in its unending quest for food to feed its young.