6 CALIFORNIA ACADEMY OF SCIENCES. 



season being at hand. It is noteworthy that the speci- 

 mens obtained previous to Dec. 31st did not show the 

 enlargement of the reproductive organs. 



The Dark-bodied Shearwaters observed were seem- 

 ingly stragglers bringing up the rear in the southward 

 migration of the species, this migration apparently com- 

 mencing during the latter part of June. The ovary and 

 testes were undeveloped in the female and the two males 

 taken, which would seem to indicate that they were not 

 going to breed. It may be such loiterers furnish the in- 

 stances of early return of 'barren birds,' the Fulmars 

 noted in the previous paper perhaps being examples from 

 Arctic regions. 



The range of the Black-vented Shearwater has been 

 but imperfectly defined, even the fact of its abundance 

 off the coast of middle California remaining unknown 

 until my recent investigations. In the light of the winter 

 migration discovered, it seems probable that this species 

 extends to the boreal latitudes reached by its Dark-bodied 

 congener, which has been reported on the Asiatic side 

 from the Kurile Islands (Salvin, 'Ibis,' 5th ser., vol. vi, 

 p. 355). At the antipodes this latter species is affirmed 

 to nest on the Chatham and other isles in New Zealand 

 seas, its habitat apparently extending as many degrees 

 south as north of the equator. The condition of the gen- 

 erative organs of the specimens taken in June and July 

 off Monterey suggests the probability that it does not 

 breed in the Northern Hemisphere, but simply passes the 

 interval of the southern winter there. This is perhaps 

 true also of the Slender-billed Shearwater, which has a 

 similar latitudinal distribution and is known to nest in 

 New Zealand and the vicinity of Tasmania (Buller, Hist. 

 Birds N. Z., 2d ed., vol. ii, p. 230). The observations 

 of Mr. Brewster (Proc. Bost. Soc. Nat. Hist., vol. xxii, 

 pp. 403-405) appear to establish that Wilson's Petrel and 



