Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: BIRDS’ EYES. is a curious fact that the eyes of birds are very large in proportion to the size of the head and brain. This is not generally apparent in the living bird, because much of the eyeball is concealed by the skin and feathers. But when the skin is removed the eyes are seen to be enormous. There is always a good reason for every structure, and we shall presently see why the organs of sight are so enormous in proportion to the brain. The fact is, that the eye of a bird has to perform far more complicated tasks than fall to the lot of human eyes. In the first place, the bird is a winged creature, passing much of its time in the air, and flying with a speed which it is difficult to realise. Take, for example, one of the short-winged birds, such as the common sparrow, and note the rapidity of flight with which it darts past a window. If we take one of the long-winged birds, such as the swift or the kite, wemust multiply the swiftness exceedingly. It is therefore evident that if the eyes were
short-sighted, the bird would be always in danger of striking itself against branches of trees and similar objects, and so killing itself. When telegraphic wires were first put up, numbers of birds were found lying dead beneath them, and were supposed by those who did not understand electricity to have been struck dead by an electric message which passed through their bodies while they were perching on the wires. The fact is, that they were killed by striking the wires, and not by electricity, which could not pass through the body of a perching- bird. One day, when I was in Paris, I saw a heedless sparrow fly against an overhead wire and fall to the ground in two pieces, the head having been severed as neatly as with a knife. It is worth noticing that, at the present da…