130 PROCEEDINGS OP THE ACADEMY OP 



exactly how the great changes of plumage to which the hird is subject, are 

 produced. 



Adult. Bill horn, deepening into black ; feet black. Pileum and occipital 

 crest brownish-black ; this color extending much below the eyes, and occupy- 

 ing the feathers on the ramus of the inferior maxilla. Acuminate feathers of 

 the neck light yellow. Back, wings, tail, upper wing coverts, under tail 

 coverts as far as the flanks, deep blackish-brown. Under parts, from chin to 

 abdomen, and neck all round, (except the yellow acuminate feathers,) pure 

 white. 



The above is the plumage of the fully adult bird, and is comparatively not 

 often met with. A more usual state of plumage (described by Lawrence and 

 figured by Audubon* as " fully adult, : ') is as follows : 



Nearly adult. Generally as in the preceding, but with a row of brown spots 

 across the breast ; the sides under the wings transversely barred with white 

 and brown ; the purity of the dark color of the abdomen interrupted by some 

 touches of white. The legs still wholly black, and the tail feathers projecting 

 as much as in the fully adult. 



Now, as a somewhat younger stage than the preceding, we have the fol- 

 lowing 



Intermediate stage, (No. 1275.) The band of dark spots across the breast 

 has widened and enlarged, so that the whole breast appears brown, mottled 

 with white ; the sides under the wings are conspicuously barred with white 

 and brown ; the white of the under parts is continued down over the abdomen 

 to the under tail coverts ; the pure brown of these parts which obtains in the 

 adult, now only appearing as transverse bars among the white. The upper 

 tail coverts and some of the wing coverts are barred with white. The bases 

 of the primaries are inferiorly white. The central tail feathers now only 

 project an inch. The tarsi are quite changed in color ; they are now irregularly 

 blotched with chrome yellow, the hind toe and nail being of this color. 



The above changes are very gradual, and readily identifiable ; the quo modo 

 of their production may be thus summed up : In the adult the white and 

 brown occupy distinct and well-marked regions ; and the two colors are 

 separated by trenchant lines of division. The younger the bird, the more 

 this distinctness of definition of colors is lost, the white invading and barring 

 the brown, and the brown invading and mottling the white, wherever the 

 two join. Then also the feet lose their black, and are variegated with yellow. 



Besides the above, we find a state characterizable thus : 



Dusky stage. The bird is very nearly unicolor : blackish-brown all over; 

 this color deepening into quite black on the pileum ; lightening into fuliginous 

 brown on the abdomen, with a slight gilding of the black on the sides of the 

 neck. The whitish bases of the primaries exist. The feet are in the chromo- 

 variegated condition. The central tail feathers scarcely project half an inch. 



In the last edition of the Manuel d'Ornithologie, Temminck corrects various 

 errors committed in previous editions, and gives, as his mature opinion, four 

 " varieties" of this species. By examining his diagnoses, it will be seen at a 

 glance that his "variety C" is the fully adult plumage above characterized ; 

 of which he says truly that it is " assez rare." His " B " is our second stage ; 

 his " A " is about our third stage ; while his " D " is the fusco-unicolor stage 

 just given. In his earlier editions he maintains that this dusky stage is% 

 absolutely independent of sex ; but latterly he says that it is possible that the 

 dusky birds are females ; the white-bellied ones males. Ornithologists main- 

 tain very diverse views on this subject ; but I believe it is generally supposed 

 that this state of plumage is not indicative of either sex, but simply of imma- 

 turity. 



Now I think that the four' plumages which Temminck describes as adults 



* I have Audubon's original specimen before me. It agrees minutely with his plate; ami is also 

 the specimen from which Lawrence's description in the General Report was taken. 



[May, 



