in LOR AND SEASON. 37 



plumage, and not assume the dress of maturity until the 

 second or even the third Bpring, which is the case with 

 the Orchard Oriole. 



Color <!/<</ Season. — Quite apart from the changes in 

 color due to age, a bird may throughout 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 sparrowlike dress resembling that 

 of his mate. The Scarlet Tanager sheds his gay body 

 plumage and puts on the olive-green colors of the fe- 

 male, without 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 Molt* — These changes in plumage, as far as they 

 are understood, are accomplished by the molt, frequently 

 followed by a wearing off 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 without 

 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 

 Plumages of the Smaller Land Birds "f Eastern North America, Pro- 

 ceedings <>f tin- Philadelphia Academy of Natural Science, 1896, pp, 



liis-ii;:, two plates. 



