198 ORNITHOLOGICAL EXPLORATIONS. 



planation. Among the iitarmigans shot ou Bering Island cluiiug the 

 winter 1882-'83 a considerable proportion are found having a number of 

 dark feathers among the white ones. Some of these feathers were 

 wholly dark colored, other ones only partially so, with larger or smaller 

 dark spots on the white feathers, sometimes symmetrically, sometimes 

 only on one web, sometimes obliquely over both. Not less than about 

 6 per cent, among some seven hundred specimens examined were thus 

 marked, males and females, a proportion which held good throughout 

 the winter, at the beginning, in the middle, and at the close. 



Such dark feathers among the white ones also occur in the allied 

 species, though not to such an extent, that I am aware of, and has 

 probably given rise to the theory that the dark feathers of the fall 

 plumage fade into the white winter garb without moulting. But if 

 any proofs are needed against this hypothesis my specimens will fur- 

 nish them. In the first place, I found partially dark feathers in their 

 sheaths, and in the second place,- these dark feathers of the winter 

 plumage are totally different from those of the fall plumage of which 

 they ought to he the remnants! The postaistival plumage of the males 

 is of a saturated ferruginous brown, with fine, but distinct, blackish 

 vermiculations and cross-bands. The dark feathers of the male's win- 

 ter plumage are almost wholly black, sometimes with some faint and 

 indistinct brownish undulations and shadings, consequently more like 

 the feathers of the preiestival or sjiring plumage. The ground color of 

 the summer plumage of the females is of an ochraceous orange color, 

 with rather broad blackish cross-bars ; the dark feathers among the 

 white ones in winter are brown, very finely undulated and vermiculated, 

 and consequently very much like those of the fall plumage of the malel 



One of these females {l^o. 92717) had a very well pronounced black 

 loral stripe too, as had in fact not a few of them, but upon dissection 

 I found the ovary normal ; no trace of sterility, nor indication of any 

 disease.* 



The most interesting specimen in regard to this dark winter plumage 

 is a female (No. 92714), the sex of which was also determined by dissec- 

 tion, and which had the ovary well developed and normal. Besides 

 having a mere indication of a black eye-stripe and several brown feath- 

 ers on the hind neck, the seventh, eighth, ninth, and tenth primaries 

 and the eighth primary covert on each wing are not white, as is otherwise 



* This case shows how hyper-cautious the collector must be in indicating the sex. 

 He should make it a rule nevtr to mark the sex upon a label if he has not exaioined 

 the specimen by dissection. 



