Birds who live on the ground need dresses of dull colors, or they would not be very safe. The ostrich mother, who makes her nest in plain sight on the sand, is dressed in grayish brown. When she sits on the eggs, she lays her long neck flat on the ground before her; then she looks like one of the ant-hills that are common on the plains of Africa, where she lives. The South American ostrich, or rhea, fluffs out her feathers and looks like a heap of dry grass. The male ostrich is dressed in showy black and white, and he stays away all day, but takes care of the nest at night, when his striking colors cannot be seen. VII HOW HE CHANGES HIS CLOTHES IT takes a bird weeks to put on a new suit of clothes. He has nothing but his feathers to protect him from cold and wet, and as feathers cannot grow out in a minute, he would be left naked, and suffer, if he lost them all at once. So he changes his dress one or two feathers at a time. Some day a feather will drop from each wing. If you could look, you would see that new ones had started out in the same place, and pushed the old ones off. When the new ones are pretty well grown another pair will fall out. If all dropped out at once, besides suffering with cold he would not be able to fly, and he could not get his living, and anybody could catch him. But losing only one from each side at a time, he always has enough to fly with. It is the same way with his tail feathers. He loses them in pairs, one from each side at the same time. [Illustration: AMERICAN GOLDFINCH] The soft feathers that cover his body drop out one by one. Thus all the time he is putting on a new suit he still wears part of the old one. In this way he is never left without clothes for a moment. Most birds put on their new suits just after the young ones are grown up, and before they all start for the South to spend the winter,--that is, with many of our common birds, in August. At that time they are rather shy, and stop singing. If you did not see one now and then, you might think they were all gone. Sometimes the new fall suit is not at all like the old one. There is the goldfinch, all summer in bright yellow. When he comes out in his new suit in August, it is dull-colored, much like the one his mate wears all the year, and in winter, when goldfinches fly around in little flocks, they look nearly all alike. In the spring, the male goldfinch comes out again in yellow. He has two suits a year,--a bright yellow one in the spring, and a dull olive-green for the winter. But his new spring dress is not a full suit. The yellow of the body is all fresh, but the black wings are the same the year round.