He wants no fire to keep him warm, for when it is too cold he spreads his wings and flies to a warmer place. A bird has really no need of a house,--excepting when he is a baby, before his eyes are open, or his feathers have come, or his wings have grown. While he is blind, naked, and hungry, he must have a warm, snug cradle. So when the bird fathers and mothers come in the spring the first thing they do is to find good places and build nice cradles, for they are very fond of their little ones. They spend the spring and summer in working for them, keeping them warm, feeding them till they are grown up, and then teaching them to fly and to take care of themselves, so that when summer is gone they will be ready to go with the other birds to their winter home. THE NESTLING III THE BIRD'S HOME EACH bird mother has her own way of making the nest, but there is one thing almost all of them try to do, and that is to hide it. They cannot put their little homes out in plain sight, as we do our houses, because so many creatures want to rob them. Squirrels and snakes and rats, and some big birds, and cats and many others, like to eat eggs and young birds. So most birds try, first of all, to find good hiding-places. Some tiny warblers go to the tops of the tallest trees, and hide the nest among the leaves. Orioles hang the swinging cradle at the end of a branch, where cats and snakes and naughty boys cannot come. Song sparrows tuck the little home in a tuft of weeds, on the ground, and bobolinks hide it in the deep grass. After a safe place is found, they have to get something to build of. They hunt all about and gather small twigs, or grass stems, or fine rootlets, and pull narrow strips of bark off the grapevines and the birch-trees, or they pick up strings and horsehairs, and many other things. Robins and swallows use mud. [Illustration: BALTIMORE ORIOLE AND NEST] As they go on building, the mother bird gets inside and turns around and around to make it fit her form, and be smooth and comfortable for her to sit in. When a nest is made, it must be lined. Then some birds go to the chicken yard, and pick up feathers, and others find horsehairs. Some of them pull off the soft down that grows on plants, or get bits of wool from the sheep pasture, or old leaves from the woods, and make it soft and warm inside. Some bird homes are only platforms, where it seems as if the eggs must roll off, and others are deep burrows, or holes in the ground, where no one can get in. Some are dainty baskets hung between two twigs, and others are tiny cups of felt with lichens outside. Each species of bird builds in its own way. There are as many different ways to make nests as there are kinds of birds to make them. Then after all the trouble birds have taken to build a nest, they seldom use it a second time. If a pair have two broods in a season, they almost always build a new one for each family.