That is the way some birds manage to put on their spring dress in the fall. The solid color is the color of the spring, but it is hidden or veiled by tips of another color for winter. The meadowlark changes in this way. In the winter his coat is brownish, or buff. In the spring these tips are worn or broken off, and he comes out in yellow and black. Another change, even more curious, is made by some birds, who all winter wear white spots, or light scolloped edges to their feathers, and in spring the spots are gone. In these, the white or light parts only break off, as sharply as if cut with scissors. They leave the edges of the feathers notched in queer ways, but as they lie over each other that does not show. [Illustration: BLACK AND WHITE WARBLERS (MALE AND FEMALE)] Birds in this way can change color without changing their feathers. While moulting but once a year, they can show two suits, and by partially moulting twice, can show three suits. Another thing about the color of feathers is interesting. Some colors, such as black, and red, and brown, are caused by coloring matter in the feather. But other colors are only an effect of the way the feather is made, whether it has ridges on it, or certain minute specks under the surface, which seem to act as prisms (says Dr. Newton), and reflect the light in different colors. For instance, green is always due to some shade of yellow coloring matter under a surface full of lengthwise ridges, and other colors are made in similar ways. These curious facts have been found out by that tell-tale little instrument the microscope, and no doubt it will reveal many more secrets in time. Color is useful to birds, as well as beautiful. Its great use is to conceal them from their enemies, and they show that they know this by their conduct. When a bird is of the color of dead leaves, or the sand, he has only to flatten himself and keep still, and he is hidden. Such a bird on the nest will often let one come close, and even stroke her, while relying on her color to be unseen. A sitting ruffed grouse will do so. But if snow falls, the same bird is very wild, for she knows she can be seen in the snow. I have seen a striped bird,--black and white warbler,--when frightened, flatten himself on a branch, where he looked so much like the bark that he could not be seen. Ground birds are mostly in mottled colors of the ground. The whip-poor-will, whose habit it is to rest on a log all day, wears colors that hide him as well as if he were under the log. The striking colors on a bird are often bidden when he is at rest, but show plainly when he flies. When a flicker stands quietly on a fence he is all in rather dull colors, but when he flies he shows a large snow-white spot on his back, so that as far as one can see him he may be known.