PASSERINE BIRDS OF NEW YORK 119 



Alar Tracts 492 Ventral Tract 465 



Humeral Tracts 96 Caudal Tract ......... 55 



Capital Tract 1385 Lumbar Tracts 70 



Dorsal Tract 506 Crural Tracts 166 



Total 3235 



The actual number of feathers, however, is not nearly so im- 

 portant as their size, and I will venture to assert that over 50% 

 of the total number are no larger than those shown on plate I, 

 fig. 17, while hundreds of them are almost microscopic. The 

 Bobolink is one of the species cited by several observers as 

 changing from buff to black without feather loss because no 

 feathers are found in cages. The most plausible evidence yet 

 advanced is Dr. A. P. Chadbourne's ('97) but even this ob- 

 server admits that his cage was not protected by any netting. 

 Furthermore he leads us to expect tremendous feather-loss and 

 estimates the number of feathers, kind not specified, at 2634. 

 As most of the feathers of a Bobolink are extremely small, a 

 wing beat would readily drive them out of the cage. Suppose 

 now a caged bird possessed the dark wings and tail often found 

 in autumn. Without moult the loss of their buff edgings com- 

 bined with the ragged state in which we find them later might 

 easily produce a color that would pass for black and if numer- 

 ous body feathers had been knocked out, as is often the case, 

 before observations upon a specimen began, it would be easy 

 to overlook a partial moult. I know from personal experience 

 how easy it is to fail to find by examination the tiny feather 

 sheaths which are quickly lost even before the black portion of 

 the yellow tipped feathers pushes out into view among the con- 

 cealing buff feathers. Having pointed out some of the possibili- 

 ties of error in observations, I may add that Dr. Chadbourne's 

 Bobolink and one or two others that have not been preserved by 

 their owners are certainly unique. There is no lack of evidence 

 that other caged Bobolinks undergo a fairly complete moult in 

 the spring and I have personally watched several birds and seen 

 others that had completed the process. Even admitting that 

 some birds can and do turn black as asserted, it is no proof 



