BREWSTER : BIRDS OF THE CAPE REGION, LOWER CALIFORNIA. 17 



taken at Monterey, California, in the winter of 1896-97 by Mr. Alvin Seale, I 

 have become convinced that the doubts which certain writers have expressed i 

 concerning the specific distinctness of hijpoleucics and craveri are without foun- 

 dation. The chief characters which appear to distinguish the two birds are as 

 follows : — 



B. hypolpucns. Upper parts blackish slnte often with a decided tinge of bhiish ashy ; 

 lining of wings clear, immaculate white; inner webs of outer primaries nearly 

 or quite pure white to within a short distance from the tips ; many of the dark 

 (bluisli slate) colored feathers on sides of body conspicuously tipped with white. 



B. craveri. Upper parts seal brown ; lining of wings smoky gray or grayish white, 

 many of the feathers with conspicuous spots or blotches of faded ashy brown; 

 inner webs of all the primaries plain brown only a shade or two lighter than 

 that of the outer webs and never approaching white save at the extreme bases 

 of the feathers, which are sometimes brownish wliite ; dark colored featliers on 

 sides of body without light tipping. 



The clear slaty tone of the upper parts in my examples of Mjpoleucus may 

 be due to the fact that the birds were all taken at somewhat earlier dates in 

 the winter than any of my specimens of craveri, but the other characters above 

 mentioned are obviously not of a kind likely to be materially affected by mere 

 seasonal differences of plumage. 



The dissimilarity in respect to the color of the wing lining has been long 

 known, only its constancy as well as its significance having been questioned. 

 In the specimens before me it is absolutely constant, at least within certain 

 limits. Most of my specimens of craveri have the under coverts conspicuously 

 blotched and spotted with slaty or brownish on a smoky or ashy white ground, 

 but in a few birds the lining of the wing is pure white and, at first glance, 

 apparently almost immaculate. On close inspection, however, I find that 

 all such specimens in my series have the white or whitish on most of the 

 under wing coverts confined to the tips and edges of the feathers, their central 

 portions being either slaty or brown. "When the plumage is disarranged these 

 dark markings become at once conspicuous. 



The coloring of the wing lining varies greatly in young birds. The natal 

 down which, at first, completel}^ clothes the under surface of the wings is 

 apparently always uniformly dark (reddish brown). Among the birds which 

 have shed this down some have the under wing coverts dark slate or slaty 

 brown relieved by only a few whitish markings on the tips of the feathers. 

 With others of apparently similar age the under surface of the wings is not 

 darker than in most of the adults. As a rule, however, the ground color of 

 the under coverts appears to become lighter as the bird grows older, but the 

 brown on the centers of the feathers evidently persists through life. 



1 Dr T. H. Streets and Mr. W. R. Ogilvie-Grant have suggested that craveri 

 may be merely hi/jioleucux in f nil breeding plumage, while Mr. Anthony has "thnuglit 

 it possible that it may prove to be a plumage of the young carried through one or 

 more moults." 



VOi,. XLL — NO. 1 2 



