10 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Ser. 



worn off and faded. The primaries are therefore not renewed 

 entirely until the adult plumage is practically assumed in all 

 other particulars. Occasionally there are specimens in this 

 stage with old, worn, faded feathers in the forehead. The 

 Academy's series of immature birds contains specimens in all 

 stages of moult. 



The postnuptial renewal of the plumage is shown very well 

 by a series of birds from Duncan Island taken in August. A 

 similarly large series taken on that island in December is in 

 rather worn plumage, including primaries. Evidently there 

 is a partial prenuptial renewal of the plumage, for several of 

 these specimens show a few new feathers appearing about the 

 head, the neck, and the interscapular region. A few of the 

 specimens taken on Hood Island in latter September and early 

 October, 1905, give similar evidence. Several birds taken 

 there in early February have well-worn rectrices and remiges, 

 apparently evidencing that these feathers are moulted only 

 annually. These specimens show pin-feathers in the head, 

 breast, abdomen, and back. They are all females, no males 

 being taken at that time. 



In adults, as in immature birds, the last trace of moult is in 

 the small coverts near the carpo-metacarpal joint. It is also evi- 

 dent that the young moult into the adult plumage, excepting 

 primaries, at practically the same time (or perhaps a little 

 later,) that the postnuptial moult takes place in the adults. 

 The complete renewal of the primaries seems to be somewhat 

 later, as shown by specimens of nearly adult birds taken on 

 Duncan Island in December. In other words, birds in the 

 post Juvenal plumage are practically indistinguishable from 

 adults in postbreeding plumage. 



A male, taken by Mr. Beck on Narborough Island on April 

 18, is evidently a breeding bird, and is in worn plumage 

 without signs of moult. A female from Jervis Island, De- 

 cember 21, shows a large patch of pin-feathers on one side 

 of the abdomen. This renewal was evidently caused by an 

 accidental loss of feathers. 



Birds showing albinistic tendencies were not uncommon, 

 and were collected on Abingdon, Duncan, Gardner-near-Hood, 

 and Hood islands.^ In one of the most extreme cases in the 

 series, a female (No. 252 C. A. S.), the black of the tertiaries, 



^See also BuU. B. O. C, v. 10, p. 84. 



