1896.] NATURAL SCIENCES OF PHILADELPHIA. 109 



material. Owing to this lack of specimens, I have no doubt that 

 alterations will have to be made in my accounts of the molt in 

 several species, in the light of future investigation. I nevertheless 

 think it desirable to publish, at once, such information as I have 

 collected, as a basis for future work. 



In the first part of this paper will be found a general account of the 

 methods of plumage change, based upon my studies, and all state- 

 ments will be understood to refer only to the groups here under con- 

 sideration. As no general paper on molting has aj)peared recently, 

 it seemed best to treat the subject at some length in this connection ; 

 but it must be understood that I do not claim originality for all the 

 statements given below as many of the facts have long been known. 

 I have, however, made no statements that have not seemed to be 

 verified by my own investigations. The second part consists of brief 

 accounts of the molts and seasonal plumages of most of the smaller 

 land birds of eastern North America, from the Cuckoos through 

 the Passeres in the order of the American Ornithologists' Union 

 Check List. The Raptores, Columbse, Gallinse and all the Water 

 Birds have been omitted for want of sufficient material for their 

 proper study, though they will probably exhibit still more interest- 

 ing facts than those furnished by the groups here under consideration. 



The difficulties that present themselves in a study of this nature 

 are many. Chief among them is the impossibility of telling the age 

 of most of the specimens upon which we must base our investigation. 

 The study of live birds is, of course, out of the question, and even 

 were it possible the results would not prove satisfactory, as it has 

 been shown that plumage changes in captive birds are often abnor- 

 mal. 



Thrown back upon a study of prepared skins, our only method of 

 telling what year in the life of the bird a certain plumage represents, 

 is by having a sufficient series of specimens, taken while actually in 

 the molt, to connect the various known plumages. Such series are 

 at present very hard to obtain, as has already been stated, and we 

 are, therefore, often forced to judge from comparison of series taken 

 before and after the molts, which is of course much less satisfactory. 

 Many specimens, however, which are apparently not molting, often 

 show traces of an old plumage which has just been lost or a new one 

 just appearing, when the feathers are carefully raised on various 

 parts of the body ; and much of ray information has been gained 

 from such specimens. 



