368 PROCEEDINGS OF THE ACADEMY OF [1897, 



ON THE ANNUAL MOLT OF THE SANDERLING. 

 BY WITMER STONE. 



In March, 1896, Mr. Frank M. Chapman published a paper en- 

 titled " The Changes of Plumage in the Dunlin and Sanderling," * 

 his object being chiefly to controvert the theory of Gatke and others 

 that these and other birds acquired their nuptial dress by an 

 actual change in the color of the feathers of the winter plumage. 



Mr. Chapman demonstrates conclusively, with the aid of a large 

 series of specimens, that this change is effected by an absolute re- 

 placement of the old plumage by new and differently colored 

 feathers. 2 In the case of the Sanderling, Calidris arenaria, Mr. 

 Chapman describes the plumage changes of the bird in some detail, 

 and in speaking of the annual molt says : — 



" There is no reason to doubt that the Sanderling, like other 

 birds, undergoes a complete molt after the breeding season ; never- 

 theless, not one of my twenty August specimens shows any signs of 

 molt in progress in the wings or tail. In the larger number, how- 

 ever, the remiges and rectrices are in an apparently fresh and un- 

 worn condition, and I assume that in most cases these important 

 feathers are acquired before the migration is begun. This would be 

 in July, a month which, as I have said, is not represented in my 

 series." 



At the time this was published I agreed quite as fully with this 

 view as I do with the other conclusions reached by the author in 

 his admirable paper, but specimens recently submitted to me by my 

 friend Mr. William L. Baily, taken at Cape May, N. J., August 14th, 

 1897, show the flight feathers in full molt, and prove that the molt 

 of these feathers does not akvays take place before the migration, 

 while subsequent examination of additional material leads me to 

 think that in the large majority of cases they do not begin to molt 

 until the migration has begun. 



These Cape May specimens also tend to emphasize a fact which 

 Mr. Chapman has curiously enough stated in the sentence imme- 

 diately preceeding the one above quoted, and which all who have 

 studied molts know to be only too true, viz. : " the necessity for 



1 Bull. Araer. Mus. Nat. Hist., Vol. VIII, pp. 1-8. 



2 The author pointed out the same fact independently in a paper which ap- 

 peared April 14, 1896. Proc. Acad. Nat. Sci. Phila., 1896, p. 125. 



