It was really a dangerous thing which Rob proposed to do, but boys do not always stop to figure about danger when there is something interesting ahead. Passing the rope through his belt as he had said, he kept hold of the free end with one hand, and so, picking his way from one projecting point to another, he began slowly to pass down the seaward face of the rock, which proved to be not so steep as it had seemed from below, although ridged here and there with sharp walls or cut banks, which crossed from almost one face of the pinnacle to the other. Rob's daring was rewarded by the finding of countless numbers of nests of the sea-parrots, which were bored back straight into the face of the cleft. "Here they are, boys!" he called back, his voice being even by this time barely distinguishable amid the clamor of the gulls and other wild birds which continuously circled about. Rob thrust his arm into one of these holes in the cleft, and was lucky enough to catch a female parrot by the neck and to pull her out without any injury to himself. For a time he examined the bird, laughing at its awkward movements when he flung it on the rocks at last, uninjured. Then he edged on along the rock face, his foot on a sort of narrow shelf and his body guided by the supporting rope. "I can get a lot of them here!" he called up to his friends. A moment later he pushed his arm again into an aperture among these nests. At once he uttered a sudden, sharp cry and pulled out his arm. His finger had been bitten almost to the bone by the hornlike beak of one of the birds. The pain of this alone would have been bad enough, but now it caused a still more serious accident. As Rob shook his bleeding finger at his side, and half raised his left arm to fend off the rush of two or three angry wild birds, he suddenly slipped with one foot at the edge of the narrow shelf on which he stood, and before he could catch his balance or do more than tightly grasp the free end of the rope which passed under his belt, over and down he went. For one swift instant he saw the long, white, curling breakers on the beach below him, for he fell face downward, his body or feet scarcely touching the rocky wall. He never knew quite how it happened, but in some way the rope jammed at his belt, and before he had fallen more than fifteen or twenty feet he found himself fast, but swinging like a plummet at the end of the line, entirely out of touch, with either hands or feet, with the face of the rocky wall. Below him he could faintly hear the murmur of the sea on the rocks a hundred and fifty feet below. Above him he could see nothing but the edge of the shelf over which he had fallen. As soon as he could control himself, he called aloud again and again, but he got no answer. If his friends above heard him, their answer was drowned by the clamor of the wild birds. Here, then, was the most serious situation in which he had ever found himself in all his life.