The black robin is one of the world’s rarest birds. It is a small, wild bird, and it lives only on the island of Little Mangere, off the coast of New Zealand. In 1967 there were about fifty black robins there in 1977 there were fewer than ten. These are the only black robins left in the world. The island has many other birds, of course, of different kinds, large and small these seem to multiply very happily. Steps are being taken to preserve the black robin. Detailed studies are going on, and a public appeal for money has been made. The idea is to buy another island nearby as a special home for threatened wild life, including black robins. The organizers say that Little Mangere should then tie supplied with the robin’s food— it eats only one kind of seed. Thousands of the required plants are at present being cultivated in New Zealand. The public appeal is aimed at the conscience of mankind, so that the wild black robin will not die out and disappear from the earth in our lime at least. Is all this concern a waste of human effort? Is it any business of ours whether the black robin survives or dies out? Are we losing our sense of what is reasonable and what is unreasonable? In the earth’ s long, long past hundreds of kinds of creatures have evolved, risen to a degree of success—and died out. In the long, long future there will be many new and different forms of life. Those creatures that adapt themselves successfully to what the earth offers will survive for a long time. Those that fail to meet the challenges will disappear early. This is Nature’s proven method of operation. The rule of selection—the survival of the fittest—is the one by which human beings have themselves arrived on the scene. He, being one of the most adaptable creatures the earth has yet produced, may last longer than most. You may take it as another rule that when, at last, man shows signs of dying out , no other creature will extend a paw to postpone our departure. For Nature, though fair, is a hard-hearted mistress. She has no favorites. Life seems to have grown too tough for black robins. I leave you to judge whether we should try to do something about it. The black robins are getting fewer and fewer because ______.