National Geographic : 1968 May
EKTACHROME© NATIONALG and drained it. And poor Spot, the victim of his own procrastination, got no share even of the reward set out as a consolation prize for him, for when we exchanged the red frag ments for hen eggs, Lame and Number Two chased him away. By the time we left Ngorongoro Crater, we felt that our research was off to a good start. We knew that stone throwing was the normal response of many Egyptian vultures to egg shaped objects that could not be picked up. This was manifestly true even when such an object was larger than any living bird's egg, and even when it was red or green. We had seen, too, that none of the vultures paid the slightest attention to a white cube about the size of an ostrich egg-which sug gests that shape may be the major factor that stimulates stone throwing (page 637). Much work, however, remains to be done, and we plan to return to the crater later this year. We hope to rear an Egyptian vulture ourselves, away from its own kind, to find out if the impulse to throw stones is inborn an inherited characteristic. We feel quite sure it is not, for once we saw a young Egyptian vulture try for 30 minutes to peck open an ostrich egg. When he gave up, an even young er bird moved in, picked up a stone, and broke the egg in six minutes. This suggests, of course, that each bird must learn the skill for itself. But maybe the method of breaking small eggs by throwing them is innate-and this we may also learn from a tame bird. I must end with a confession: It is not sim ply to further scientific knowledge that I enjoy sharing parts of the Egyptian vulture's life. I have become a vulture lover! Not of all vul tures, but certainly of the white bird with the yellow face and dark beak, the aloof bearing, and the overwhelming passion for eggs that has made it one of the few animals known THE END 641 to use tools.