Page:Bird-lore Vol 03.djvu/202



Recognition Marks of Birds BY ERNEST SETON-THOMPSON Illustrated hy the Author IN general the markings of animals are believed to be either protective or directive: that is, designed either to hide the animal, or else to distinguish it and make it conspicuous or ornamental. In the bird world we have many illustrations of both kinds of colora- tion in the same individual, for many species arc protectively colored while sitting and directively while flying. Or, to put it in another way, the colors of the upper parts show chiefly when the bird is perching, and these are protective; the colors of the loiver parts and expanded wings are directive, and are seen chiefly in flying. All birds with ample wings and habits of displaying them, bear on them distinctive markings; for example: Hawks, Owls, Plovers, Gulls, etc. All bird students will recall the pretty way in which most of the Plovers let the world know who they are. As soon as they alight, they stand for a moment with both wings raised straight up to display the beautiful pattern on the wing linings; a pattern that is quite different in each kind and that is like the national flag of the species, for it lets friend and foe alike know what species is displaying it. On the other hand, birds like the Hummingbird, whose wings move too rapidly for observation, are without color pattern on the under side. These markings, no matter which categor they belong to, arc pur on the bird first of all to be of service to its own kind. That is certain, as certain as the main truth of evolution; for, as Darwin long ago stated, if it can be shown that any species has acquired an thing that is of use only to some other species, then the theory of evolution b natural selection must fall to the ground. Hut this ilocs not sa- that an aci|uircii characteristic may not also be of use to another species. Thus the directive and recognition marks of the Hawks ami Owls as illustrated on iin plate are, of course, first to