THE BIRDS OF THE PRIBILOP ISLANDS. 427 



There is no noticeable variation in the immature birds, or, in fact, in the adults. 

 Young birds had up to the end of July completed the growth of the wings and tail, 

 but no new feathers of the winter plumage had appeared. In the young the bill is 

 very dark dusky and in the summer adults it is black. Winter specimens of all ages 

 from other localities have pale-yellowish colored bills, with dark tips. No specimens 

 are at hand showing the change, but as the bills of winter birds (=0,46-0,48-0.50) are 

 much shorter than in summer specimens (=0.51-0.53-0.57), it may be that the change 

 occurs by a molt or renewal of growth. After the young leave the nest they remain 

 about their rocky home for some days and are then taken by their parents to the 

 killing grounds. The nest is quite bulky, 6 inches or more jn diameter^ made outside 

 of old, coarse grass stems and lined thickly with new, small, and apparently well- 

 chewed clean grass stems and a few white feathers with a little hair. Sometimes a 

 little moss is added to the outside material. The eggs are large, the shell very thin 

 and pinky when fresh; white with a slight gloss in the cabinet. A set is five or six, 

 and they measure from 0.93 by 0.68 to 0.96 by 6.71 and 0.98 by 0.70. Stomach con- 

 tents, two specimens : "A carabid beetle, crane flies, grass seeds, and fruit skin formed 

 the contents of the stomachs of these birds." — {8. D. J.) 



KECBNT LITBKATUBE OP THE AVIFAUNA OF THE PRIBILOF ISLANDS. 



Quite a number of very important reports dealing with the birds of this region 

 have been issued by various departments of the United States Government; in fact 

 little of importance has been effected by private means. They are the results of the 

 labors and experiences of a number of naturalists who have spent from a season to 

 several years in the region. The specimens, numbering perhaps several thousand, 

 and containing many types and unique and unusual specimens, are in the United 

 States National Museum collection in Washington, instead of being scattered through 

 many widely separated collections, or perhaps lost, as they might have been if more 

 of the pioneer work in this region had been done otherwise than under Government 

 auspices. The wisdom of the late Prof. S. P. Baird, Secretary of the Smithsonian 

 Institution, and of the various Secretaries of the Treasury and other Government 

 officers in assisting and permitting in every way in their power the detailing of 

 naturalists to accompany the various naval and revenue vessels which have had busi- 

 ness in those waters, has been many times proved, and the work done in the many 

 branches of science, as shown in the various reports, has certainly justified the under- 

 takings. Our knowledge of the fauna of that region, small as it really is, would be 

 but meager if these opportunities had been neglected. In the following list I have 

 attempted to note all of these papers dealing with the birds and published in recent 

 times. I have noted especially the year in which the work was done, the Department 

 to which the author was attached, and some mention as to the extent of the results. 

 Many of the writers have visited the seal Islands for short periods, though. few had 

 opportunities for any extended collecting. Such notes as they made were incor- 

 porated in general results, and special mention was made in most cases concerning 

 one or more species of Pribilof birds. I have added also a few general works dealing 

 with the waters of Bering Sea. A very full bibliography of Alaskan birds will be 

 found in Mr. Nelson's work of 1887. 



