The black robin (旅鸫) 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._____1_____
Energetic steps are being taken to preserve the black robin._____2_____ The idea is to buy another island nearby as a special home， a "reserve"， for threatened wild life， including black robins. The organizers say that Little Mangere should then be restocked (重新准备) with the robin's food. Thousands of the required plants are at present being cultivated in New Zealand.
Is all this concern a waste of human effort? _____3_____ 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._____4_____ 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. We， being one of the most adaptable creatures the earth has yet produced， may last longer than most._____5_____ You may take it as another rule that when， at last， human beings show signs of dying out， no other creature will extend a paw (爪) to postpone our departure. On the contrary， we will be hurried out.
Life seems to have grown too tough for black robins. I leave you to judge whether we should try to do anything about it.
