155 



ill ver}^ highly colored birds, while the primaries are 

 not moulted during the first 3- ear, but attain their 

 brillianc}' either by wear or by direct change in the 

 color of the f€athe7\ the tail feathers of such birds, at 

 least in a number of species, are moulted. Any one 

 who is familiar with the color pattern of the rectrices 

 of adult Baltimore Orioles and Rose-breasted Gros- 

 beaks must be aware that there is a very strongly 

 contrasted area of either black and yellow or black 

 and white on most of the feathers. To emphasize the 

 matter let me say again that Baltimore Orioles and 

 Rose-breasted Grosbeaks both moult their entire set 

 of tail feathers during January and February, and 

 acquire by this moult the distinctive color pattern 

 which is characteristic of the adult bird. 



In the case of my Grosbeaks, with this moult of 

 the rectrices they recovered rapidly their fine appear- 

 ance, and are indistinguishable at the time I am 

 writing from wild representatives of their kind out of 

 doors. Therefore, my apprehension that they might 

 not present a fine appearance was unwarranted, for the 

 reason that I have fully explained. 



With the primaries the change seems to be' 

 effected, so far as I have observed, in a different 

 way, which I ascribe, as I have said before, partly to 

 wear of the surface of each feather, but, beside this, / 

 avi strongly inclined to the opinion that there is a physical 

 chang^e in the feather itself, which alters its appearance so 

 far as color is concerned. 



The moult was about completed by the loth of 

 February, but previous to that time I had detected a 

 slight motion of the throat and body, indicating that 

 the two males were beginning to sing. At first it was 

 hardly possible to detect anything but the faintest 

 sounds, but in a week or ten days I could discriminate 

 the song, which I shall describe as nearly as is possible 

 in words. The tone, on the whole, is extremely 



