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 guano left by untold generations of 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 the outcry and warning hisses that 
greeted my approach 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 thousands of them, nesting the full length of the island, some three 
miles in extent. With the exception of afew 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 Puffinus. Though the 
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 anything 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. Ina 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 the burrows Iam unable to say, not having visited the nesting colony 
earlier than the first week in March, when all the burrows were occupied. 
““T 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. Townsenp. 
TOWNSEND’S SHEARWATER. 
Piffinus auricularis ANTHONY, Auk, XV. 1898, 88 (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, 
1889, was found in the waters of the Cape Region some eight years later by 
1 Proc. U. S. Nat. Mus., XIII. 1890, 133, 134. 
