COLOR AND SEASON. 37 plumage, and not assume the dress of maturity until the second or even the third spring, which is the case with the Orchard Oriole. Color and Semon. — Quite apart from the changes in color due to age, a bird may througliout its life change costumes with the seasons. Thus, the male Bobolink after the nesting season, exchanges his black, white, and buff nuptial suit for a sparrowUke dress resembling that of his mate. The Scarlet Tanager sheds his gay body plumage and puts on the oHve-green colors of the fe- male, mthout changing, however, the color of his black wings and tail. The following spring both birds resume the more conspicuous coats. A more or less similar change takes place among many birds in which the male is brighter than the female, but, among land birds, when the adults of both sexes are alike, there is little or no seasonal change in color. The J/oZ^.*— These changes in plumage, as far as they are understood, are accomplished by the molt, frequently followed by a wearing oft" of the differently colored ter- minal fringe which is found on the new feathers of some birds. It has been stated that birds change color vithout changing their plumage, either by a chemical alteration in the pigment of the feathers resulting in a new color, or by the actual gain of new pigment from the body ; but I know of no instance in which this has been proved, nor do I believe that the latter change is possible. The whole subject offers an excellent field for observation and ex- periment. There is a great and as yet but little understood variation in the molting of birds. Not only may closely
- See Stone, The Molting of Birds, with Special Reference to the
Pluraages of the Smaller Land Birds of Eastern North America, Pro- ceedings of the Philadelphia Academy of Natural Science, 1896, pp. 108-167, two plates.
