172 BULLETIN 107, UXIPED STATES NATIONAL MUSEUM, 



Fall. — The fall migration, which is nothing more than a with- 

 drawal of the species from the northern portion of its breeding range, 

 occurs late in the fall, with the closing in of the ice. Nelson (1887) 

 says that. " when hunting far out at sea the Eskimo of Norton 

 Sound find them late in November about the holes in the ice." South 

 of the Aleutian Islands the species is present throughout the winter, 

 but apparently less numerous than in simimer because individuals 

 are more widely scattered on the open sea ; they are much shyer and 

 are clad in their inconspicuous winter coat of gray and while. 

 Probably many of them spend the winter wa}^ off on the open ocean. 



DISTRIBUTION. 



Breeding range. — Coasts and islands of the North Pacific Ocean 

 and Bering Sea. From California (Santa Barbara Islands and 

 Farallones), Oregon (Three Arch Rocks), Washington (Puget 

 Sound region), and British Columbia (Vancouver Island and Queen 

 Charlotte Islands) along the coast of southern Alaska and through- 

 out the Aleutian Islands; northward along the coast and islands of 

 Bering Sea to Bering Strait; and from the Kurile Islands and the 

 Commander Islands northward along the Siberian coast to East Cape 

 and Koliutschin Bay. Perhaps rarely north to Cape Lisburne, 

 Alaska. 



Winter range. — From the Aleutian Islands and the Pribilof Islands 

 southward to California (San Clemente Island) and northern Japan. 



Spring migration. — Migration in spring is limited to the return of 

 the birds to their breeding places from the near-by sea. In Norton 

 Sound, Alaska, this takes place from the last of March to the first 

 of April, if open spaces occur in the sea ice. First arrivals at the 

 Commander Islands were noted March 14. 



Fall migration. — They desert the breeding localities as soon as the 

 young are raised and resort to the ocean in the vicinity. About 

 Norton Sound they sometimes occur as late as November. 



Egg dates. — Farallone Islands: 63 records, May 3 to July 9; 32 

 records, June 1 to 26. British Columbia and Washington: 21 rec- 

 ords. May 9 to July 13; 11 records, June 12 to 23. Santa Barbara 

 Islands: 16 records. May 15 to July 18; 8 records, June 6 to 23. 

 Southern Alaska: 7 records, June 15 to July 5; 4 records, June 18 



URIA TROILLE TROILLE (Linnaeus). 

 MTTBRE. 

 HABITS. 



As we approached Bird Rock on June 23, 1904, the setting sun 

 shone full upon the tall, red sandstone cliffs, roughly sculptured by 

 the elements into broad shelves, narrow ledges, and deep crevices, 

 which offered lodging room for countless sea fowl, domiciled in their 



