34 PACIFIC COAST AVIFAUNA No. 12 



nestlings. It is generally conceded that the young of tlie rock lobster is the main 

 food supply of all our small California petrels, as A. W. Anthony (4) has 

 pointed out. From these the oil in the stomach must be secreted, and quite rap- 

 idly at that, for birds taken early in the morning after a night at sea contain 

 much oil and only a recognizable trace of the crawfish, in addition to a very lit- 

 tle green slime. The oil gland of this species is a dark gray in contrast to the 

 creamy color of that of socorroensis. 



One often encounters lone individuals of these birds at sea during the day, 

 flapping just above the waves in an aimless and erratic manner. A. W. Anthony 

 {!), however, secured one from a flock of some two hundred birds. They suffer 

 considerably from the depredations of the Duck Hawks, as their dessicated re- 

 mains upon the islands bear mute witness. They begin visiting the nests about 

 8 -M p. M. and are very active until shortly before dawn. Pitching in from the 

 sea they come like big black bats, rocking to the breeze and uttering their loud 

 weird call. 



36. Oceanodroma homochroa (Coues) 



Ashy Petrel 



Cymochorea Jwmochroa (1) Henshaw, Rep. Wheeler Surv., 1876, p. 277. (2) Baird, 

 Brewer and Ridgway, Water Birds N. Am., ii, 1884, p. 412. 



Oceanodroma homochroa (3) Salvin, Cat. Birds Brit. Mus., xxv, 1896, p. 356. (4) Grinnell, 

 Pac. Coast Avif., 3, 1902, p. 16. (J) Reed, N. Am. Birds' Eggs, 1904, p. 54. (6) God- 

 man, Monog. Petrels, i, 1907, p. 29. (7) A. O. U. Check-list, 3d ed., 1910, p. 57. (8) 

 Willett, Pac. Coast Avif., 7, 1912, p. 19. (9) Wright and Snyder, Condor, xv, 1913, 

 p. 88. ilU) Wright, Condor, xv, 1913, p. 229. (11) Grinnell, Pac. Coast Avif,, 11, 

 1915, p. 28. 



Olceanoclroma]. hoviochroa (12) Coues, Key N. Am. Birds, 5th ed., 1903, p. 1043. 



Fairly common in the channel at certain times. Breeds on Santa Cruz, and 

 possibly on San Miguel. G. Willett (8) found this species to be plentiful in the 

 channel between San Nicolas and Santa Barbara islands in June, 1911, and L. H. 

 Miller has an adult female that he took near the latter place April 10, 1904. 



H. Wright (9) discovered them nesting in Painted Cave, Santa Cruz Island, 

 July 10, 1912. Four eggs and one small young were all that he found, deposited 

 on the bare exposed ledges in the dark parts of the cave. On June 23, 1913, D. R. 

 Dickey (MS) visited this locality and found that apparently but one pair were 

 nesting, for after a very thorough search, a single bird was located sitting on a 

 slightly incubated egg high above the water, in one of the side pockets of the big 

 cave. 



H. W. Henshaw (1) received from Capt. Forney a specimen that was taken 

 on San Miguel, where the latter said that it bred in great numbers. G. Willett 

 (8) as well as others have made a careful search of this island without finding 

 indications of breeding petrels. It is quite possible that a few pairs may breed 

 in the caves of the main island, or on Prince Islet, but it is doubtful if the foxes 

 would allow any large colonies of small pelagic birds to become established on 

 San Miguel proper. 



