28 bulletin: museum of comparative zoology. 



" On the San Benito Islands, lying between Guadaloupe and Cerros Islands, I 

 have also found a few P. opisthomelas nesting. So far as I have been able to dis- 

 cover, there are no burrows on these islands, all the nests being in small caves, 

 which are nearly filled with deposits of gua,no left by untold generations oi Puffinus. 

 The caves are all small and the nests inaccessible, but I think that each cave was 

 inhabited by several pairs of birds, judging by tlie outcry and warning hisses that 

 greeted my approacii to the entrance. 



" About thirty-five miles south of San Benito Islands lies Natividad Island, a 

 lower and more sandy island than those previously mentioned — a condition which 

 seems to suit the requirements of the Black-vented Shearwaters to a nicety, for 

 here are found tiiousands of them, nesting the full length of the island, some tiiree 

 miles in extent. With the exception of a few rocky slopes and ridges the entire 

 island may be said to be one almost continuous colony. This island I first visited 

 in August, 1896. The size of the burrows at once attracted my attention, and a 

 closer examination revealed the unmistakable tracks of a Paffinus. Thougii tiie 

 footprints were abundant and fresh, proving that the burrows were still visited at 

 night, all of those examined were unoccupied. I again called at Natividad April 

 10, 1897, and found the breeding season at its height, each burrow containing either 

 a pair of Shearwaters or one Shearwater and a fresh egg. In no case, I think, did 

 I find an egg in a burrow with two birds. The burrows were usually about ten 

 feet in length, seldom if ever straight, but with one or two sudden turns to the right 

 or left, the nest sometimes being but two feet from the entrance though at the end 

 of a ten foot burrow. Few of the nests were over eighteen inches below the sur- 

 face, the burrows being for the most part nearly horizontal, and the loose nature 

 of the soil made walking anytliing but a pleasure, as one constantly broke through 

 into tunnels, the exact location of which it was impossible to determine. . . . 



" There was little attempt at nest-building, the eggs for the most part being laid 

 in a depression in the sand at the end of the burrow. In a few cases a number of 

 small twigs and sticks had been placed in the hollow forming a very crude nest. 

 Before the egg is deposited the burrow is occupied by both birds, and I have found 

 them on the nest at least a month before any eggs were laid. Just how early they 

 take to tlie burrows I am unable to say, not having visited the nesting colony 

 earlier than the first week in March, when all the burrows were occupied. 



" I have never heard any love notes from this species when in the burrows. 

 Their outcry at night, however, when they emerge from their nests and fly about 

 over the island, is something unique in my experience. The noise is a series of 

 choking cries coupled with a hissing, like escaping steam, the same that I have at 

 times heard them utter when disturbed in their burrows." 



Puffinus auricularis C. H. Townsend. 



Towxsend's Shearwater. 



Puffinus aurkularis Anthony, Auk, XV. 1898, 38 (Cape St. Lucas) ; XVII. 1900, 

 249-252 (Cape St. Lucas ; nesting habits on San Benedicto Island). 



This species, discovered^ at Clarion Island by Mr. Townsend in March, 

 IS89, was found in the waters of the Cape Eegion some eight years later by 



1 Proc. U. S. Nat. Mus., XIII. 1890, 133, 134. 



