Febeuary 23, 1900.] 



SCIENCE. 



293 



hepsive terms, by the way, coined by Dr. 

 Coues. The latter term may be defined for 

 convenience, as the occurrence of Dichroma- 

 tism depending entirely upon the loss of old 

 feathers which are replaced by others of a 

 different color. Both processes subserve 

 the same general purpose and result in a 

 seasonal change of color, in the present 

 example, from that of the fall to the nuptial 

 of the spring. The Pfeosoehromatic change 

 of the spring will not further be considered 

 here^let it suffice to say that beyond doubt 

 some indigo birds change color in the spring 

 by completely, or nearly so, shedding their 

 feathers. The change not due to such 

 feather loss is what interests us at the pres- 

 ent, and will necessarily be presented far 

 from exhaustively. My remarks are based 

 chiefly upon observations conducted during 

 the fall, winter, and early spring of 1898- 

 99, upon a captive male bird. In view of 

 the color of the plumage of my bird, at the 

 time I took possession of it, it must have 

 been in the adult condition, and as such 

 birds are commonly captured while in the 

 adult state, the difficulty in adapting my 

 bird to his captive condition and the heavy 

 feather loss undoubtedly resulting from this 

 may consequently, be explained. I secured 

 it October 13th, while it was nearing the 

 completion of its fall moult, which by Octo- 

 ber 28th was finished. From that date every 

 cast-off feather was carefully collected and 

 labelled. In order to be sure of obtaining 

 all, a fender was placed about the cage and 

 the room carefully, swept at frequent inter- 

 vals. In addition to this I made many ex- 

 aminations of the bird and secured such 

 specimen feathers in a fresh state as I 

 wished for microscopic examination. 



Briefly, the bird was fed mostly upon 

 millet and canary seed, appeared healthy, 

 bathed regularly, and during bright days 

 sang frequently. On March 26th, how- 

 ever, he died after an illness of three 

 days, before which he was as lively as ever. 



Examination showed constipation to be the 

 probable cause of his untimely death. The 

 color change had progressed excellently 

 however, and but little additional informa- 

 tion could have been gained had he lived, 

 excepting the period of time occupied by 

 the entire change. Data is present in suf- 

 ficient quantity, nevertheless, to enable me 

 to state the time occupied by the change in 

 certain portions of the plumage. 



The appearance of my bird as regards 

 color, October 28th, was as follows : Feathers 

 of the head and breast slightly tinged with 

 cobalt, the chief color of the feathers being 

 dull rusty. The breast thus was somewhat 

 mottled in appearance. Back rusty, the 

 concealed centers bluish. Primaries and 

 rectrices blackish with blue edges. Second- 

 aries and coverts broadly edged with rust 

 color. Lower abdomen buffy, ventral area 

 whitish. 



From October 28th till January 28th I 

 observed no marked color change, but from 

 February until the bird's death, it was very 

 noticeable. A curious and undoubtedly un- 

 normal process intervened however, and in 

 order to understand this comprehensively I 

 will tabulate the feather loss beginning with 

 the first feather shed after October 28th, 

 when it will be recollected that the bird 

 had completed its moult. 



Nov. 1, 1 contour 



" 7, 1 " 



" 12, 1 



"21, 2 contours 



"22, 1 contour 



"25, 2 contours 



" 29, 1 contour 



Nov. 30-Deo. 5, 4 contours 



Dec. 5-11, 4 " 



" 11-24, 20 " 



" 24-31, 12 " 



Dec. 31-Jan. 7, 11 . " 

 Jan. 7-23, 3-5 " daily 



" 24, 12 " 



" 25, 16 " 



" 26, 13 " 



" 27 and 28, 61 " 



Jan. 28-Feb. 11, 34 " 



