IQ EVOLUTION OF BIRDS. ers, Woodbewers, and Swifts, even some Finches and the Bobolink, that use their tail to support them when perched on swaying reeds, have the feathers more or less pointed and stiffened. Furthermore, this is just the result we should expect from a habit of this kind. But Fig. 3. — Tip of tail of (a) Downy Woodpecker and of (b) Brown Creeper, to show the pointed shape in tails of creeping birds of ditferent families. (Natural size.) I do not understand how the Woodpecker's spear-tipped tongue could have resulted from the habit of impaling grubs, and in this ease I should be inclined to regard structure as due to a natural selection which has pre- served favorable variations in the form of this organ. I have not space to discuss this subject more fully, but trust that enough has been said to so convince you of the significance of habit, that when you see a bird in the bush it will not seem a mere automaton, but in each movement will give you evidence of a nice adjustment to its surroundings. Remember, too, that evolution is a thing of the present as well as of the past. We may not be able to read the earlier pages in the history of a species, but the record of to-day is open to us if we can learn to interpret it. This may be made clearer, and the importance of a study of habit be emphasized, if I briefly outline the rela- tion between the wings, tail, feet, and bill of birds and the manner in which they are used. We are in the field, not in the dissecting room ; our instrument is a field glass, not a scalpel, and in learning the functions of these four
