1911] Sirarfh: Alaska Expedition of 1909. 37 



ou the Taku River, September 2 to 28, it was occasionally 

 observed flying along the stream. ^. ,- 



The large flocks met with in June, at least, must have been 

 composed of birds that were not breeding that year. They 

 were, as already noted, in the immature plumage, with black 

 barred tail and white head, but they were all evidently birds 

 at least a year old. One specimen (no. 9887, Behm Canal, 

 June 28) has a good many black feathers on the head, and has 

 some of the rectrices pure white and others black tipped. In 

 other words it is about intermediate between the ordinary first 

 winter (immature) plumage, and that of the summer adult, so 

 it may be taken as evidence that, in some cases at least, more 

 than one year is required to attain the perfect adult plumage. 

 This bird is undergoing molt about the head, but the newly 

 appearing feathers are all pure white. The large flocks seen 

 at Bradfield Canal (July 18 to 26) contained many individuals 

 with black heads, and one of these secured (no. 9888, July 22) 

 proved to be in worn nuptial plumage, with, as yet, no indication 

 of the beginning of the post-nuptial molt. Other individuals in 

 the same flocks were in the plumage usually worn ])y adults 

 in the winter, of which the pure white tail is in life the most 

 conspicuous feature distinguishing it from the immatures. All 

 of this is rather confusing, for in the same flocks, at the same 

 time, were to be seen birds (1) in perfect nuptial plumage, (2) 

 in first winter plumage, and (3) in second winter plumage. 



A young female (no. 9889), shot at Mitkof Island on August 

 4, is in the juvenal plumage, as described by Dwight (1901, 

 p. 56), with brown upper parts (crown, neck and dorsal region), 

 and brownish wash on the sides of the neck and breast. There 

 is a specimen in the Grinnell collection (no. 1315, J* Sitka, 

 Alaska; July 21, 1896) in similar plumage but with more 

 brown above, and the brownish wash extending quite across 

 the breast. These dark backed juvenals were seen occasionally 

 at Mitkof Island, August 1 to 13, and they were quite common 

 at Thomas Bay, August 13 to 23; but I have never seen this 

 plumage represented in the flocks that appear on the coast of 

 southern California in the fall ; it is probably molted before the 

 birds go south. 



