LIFE HISTORIES OF NORTH AMERICAN PETRELS AND PELICANS. 97 

 THYELLODROMA PACIFICA (Gmelin). 

 WEDGE-TAILED SHEARWATER. 



HABITS. 



This species seems to range entirely across the Pacific Ocean from 

 Volcano Island, south of Japan, to the islands off the west coast 

 of Mexico, including the Marshall Islands, from which it was de- 

 scribed by Salvin, and the Hawaiian Islands. Mr. A. W. Anthony 

 (1898) was the first to record it as a North American bird, finding 

 it about Cape San Lucas associated with the Townsencl shearwaters 

 in " April 23 and again in early June." 



Nesting. — Mr. Anthony (1900) found the wedge-tailed shearwater 

 breeding abundantly on San Benedicto Island, concerning which 

 he writes: 



About Cape St. Lucas, and between that point and the Revillagigedo Islands, 

 the wedge-tailed shearwater (Puftinus ciincatus) is found in abundance 

 in May and June. It probably may occur at other seasons, but as I have not 

 visited the region of the Cape during other seasons I can give no assurance 

 of its doing so. This species is of exceptional interest, as it belongs to a 

 group of shearwaters new to the North American fauna, and of which little is 

 known. I was so fortunate as to discover a large colony nesting on San 

 Benedicto Island, from which was obtained a fine series of skins with all of 

 the intergrades between the white-bellied phase of cuneatiis and the dusky form 

 described by L. Stejneger from the Sandwich Islands as knudseni. 



On first landing on San Benedicto, the 1st of May, I heard a low murmuring 

 noise which seemed to come from the opposite side of the island. Thinking it 

 might come from a rookery of seals, I started out to investigate, but soon 

 found that I was getting no neax'er the source of the noise, which possessed 

 a ventriloquial power difiicult to locate. I soon, however, found myself sur- 

 rounded by large burrows which fairly honeycombed the entire south end of 

 the island, which was so completely undermined that one constantly broke 

 through into burrows, frequently sinking to the hips in ground that had every 

 appearance of being solid. 



From many of the holes came moans and sobs in soft, low tones, inexpres- 

 sively sad and weird — the love notes of Pufflnus cuneatus. 



A number of the burrows were opened, and from each were taken two birds, 

 which fought and bit most savagely on being dragged to the light. By far the 

 greater number were in dark plumage, but many showed lighter underparts, 

 and in some cases a perfectly typical " cuneatus," with pure white under- 

 parts, was found in the same burrow with a dark " knudseni." 



At this date the burrows were about four to five feet in length, most of them 

 running in a nearly horizontal direction along the sides of the steep narrow 

 ravines that everywhere cut this end of the island. 



The soil is chiefly of fine pumrice, in some places soft and easily excavated, 

 but in others so hard as to require the use of a pick in opening the burrows. 

 In most of the excavations was a rude attempt at nest building, consisting of 

 a few sprigs of green grass and other vegetation which grew about the colony, 

 and on this meager platform were both birds, but no eggs. Nor did the con- 

 dition of the birds indicate that the actual nesting season was at hand. 



