PASSERINE BIRDS OF NEW YORK 121 



Turning now from the evidence of caged birds to that derived 

 from museum skins what do we find ? Again superfluous 

 theory, and a perversion of facts to fit, based on the most super- 

 ficial observations. Without taking pains to learn even the 

 simplest facts, our foreign brethren and some too on this side of 

 the ocean have offered triumphantly mixed plumages as proof of 

 color change without moult, and extremists believe in a rebuild- 

 ing of the worn margins of feathers, or at least in their vitality, 

 because they see with a microscope pores which exude some- 

 thing. Some writers wax eloquent upon the subject. 



" Foci " and " spreading areas of color" are observed and a 

 series of feathers showing the changing pattern are plucked out 

 and figured in blissful ignorance that all the various patterns 

 were present in the feathers when they developed at the last 

 period of moult. Just such feathers (as, for instance, some 

 from the breast of a Bobolink plate I, figs. 1-6) may be found 

 fresh and new after a moult or worn and frayed and perhaps 

 in juxtaposition with newly grown ones at a later season of 

 moult, as proved by scores of species treated in the present 

 paper. There is not the slightest evidence of recoloration, the 

 alleged changes being easily and naturally explicable, as due to 

 the normal sequence of normal moult modified by normal wear. 

 The true explanation of the plumages of such species as the 

 Rose-breasted Grosbeak {Habia liidoviciaiia), Baltimore Oriole 

 (^Icterus galbidd), Orchard Oriole [Icterus spurius), Indigo Bunt- 

 ing {^Passcriiia cyanca), Bobolink {^Doliclionyx oryzivovus) and 

 other alleged examples of color change without moult will be 

 found under these species, and all mixed plumages are readily 

 explained without resort to theory, if the fundamental principles 

 of moult are once firmly fixed in mind. I have examined 

 something like 15,000 birds during the last few years and I 

 find none which do not conform to the definite laws of moult 

 and wear which I have laid down. I often wonder at the 

 temerity of theorists who, with a mere handful of specimens 

 taken, perhaps, all at one season, do not hesitate to betray their 

 ignorance of the foundation facts of plumage. As long as they 

 do not apprehend them, their conclusions are not to be taken 



