96 BULLETIK 121, UNITED STATES NATIONAL MUSEUM. 



Flinders Island to the heads of the Tamar, a distance of eighty miles. They 

 shortly afterwards separate into dense flocks, and finally leave the coast. The 

 old birds are very oily, but the young are literally one mass of fat, which has a 

 tallowy appearance, and hence I presume the name of " mutton bird." To this 

 I may add that the young birds are very good when fresh, and the old birds 

 after being skinned and preserved in brine are excellent eating. 



Winter. — After the breeding season is over, in April, the slender- 

 billed shearwaters apparently migrate into the Northern Hemisphere 

 in the north Pacific Ocean. The northward migration route seems 

 to be mainly on the Asiatic side, probably to the vicinity of the 

 Commander and Aleutian Islands ; Doctor Stejneger (1885) suggested 

 that a few of these shearwaters might breed in that region, but it 

 now seems to be well established that the species is merely a summer 

 sojourner in northern seas between its breeding seasons in Australian 

 waters. Mr. Leverett M. Loomis tells me that this species is seen on 

 the California coast only late in the fall on the return migration to 

 its breeding grounds. The large numbers seen off Monterey between 

 the 14th and 20th of December, in 1895, by Mr. Joseph Mailliard 

 were probably belated migrants. 



The large series of slender-billed shearwaters in the collection of 

 the California Academy of Sciences is conclusive evidence of the 

 abundance of this species on the coast during the southward migration 

 in the fall. 



DISTRIBUTION. 



Breeding range. — Southern Australian and New Zealand seas. 

 Mainly in Bass Straits and vicinity (Flinders, Phillip, Big Dog, 

 Kings, and Green Islands, etc.). Also on Lord Plowe Island and 

 on New Zealand (Kaimanawa Eanges) . 



Range. — Migrates northward throughout the north Pacific Ocean 

 to the Okhotsk and Bering Seas and eastward, mainly on the return 

 migration, to the coast of North America. 



Migrations. — Northward in the western Pacific Ocean and south- 

 ward in the eastern. Dates: Commander Islands, Copper Island, 

 May 29, and Bering Island, August 22; Aleutian Islands, Unimak 

 Pass, July 29, and Unalaska, August 31 ; Alaska, Ugashik, September 

 15 ; British Columbia, Victoria, October 24 ; Washington, August to 

 November ; California, Point Pinos, October 13 to January 30. Main 

 flight passes California in November and December. 



Casual records. — Northernmost record is one taken in northern 

 Alaska (Kotzebue Sound, July 4, 1899). Latest winter record is for 

 British Columbia (one taken February 23, 1904). 



Egg dates. — Islands in Australian and New Zealand seas : Twenty- 

 three records, November 11 to March 3; twelve records, December 

 1 to 17. 



