LIFE HISTORIES OF NORTH AMERICAN PETEELS AND PELICANS. 165 



to an interestino; individual variation in the plumage of adults, 

 which liad also been noted by Mr. Anthony (1898(^) ; about three per 

 cent of the birds have more or less white on the upper tail-coverts, 

 varying from a mere trace to nearly as much as in the Leach petrel; 

 the normal color of these parts is, of course, uniform sooty. 



Behavior. — INIr. Howell contributes the following notes on the 

 habits of the Socorro petrel : 



Unlike its larger relative, this form but rarely vomits oil when handled, hut 

 will often do so on the wing when released. This oil is practically the same as 

 that of mcUinia, but sometimes contains flakes of a white mucus matter, green 

 slime, and occasionally a tiny rock lobster or crayfish. It has been stated that 

 their food consists of these latter ; and this is undoubtedly the case when they 

 are easily obtainable, which is but part of the year. I believe, however, that 

 they feed on a great variety of small sea life found at the surface and upon 

 whatever floating oil they can gather. When released from the hand socorroen- 

 sifi launches in an uncertain fashion, twisting and turning after the manner 

 that should be employed by a small drunken nighthawk. If placed on the 

 ground they poke about confusedly among the bushes. In the hand one is 

 impressed by their fragility and apparent weakness. 



DISTRIBUTION. 



Breeding range. — San Benito ami Los Coronados Islands, off the 

 west coast of Lower California. 



Range. — Pacific coasts of Mexico and southern California. North 

 to the Santa Barbara Islands and south to the Eevillagigedo Islands. 

 If this species proves to be identical with 0. monorliis, its range 

 should be extended across the Pacific to China and Japan. 



Egg dates. — Lower California : Forty-eight records, June 4 to 

 September 5 ; twenty-four records, June 22 to July 10. 



OCEANITES OCEANICUS (Kuhl). 

 WILSON PETREL. 



HABITS. 



Contributed by Charles Wendell Toivnsend. 



Few who have voyaged along the Atlantic coast or who have 

 crossed to Europe have failed to see petrels or Mother Cary's chickens, 

 as they are called. On untiring wing they skim the water, now 

 on one side, now on tlie other of the vessel, all ready to gather 

 in little bands in the wake and drop astern whenever delectable 

 morsels are thrown from the cook's galley, and then it is that, like 

 Peter of old, they walk upon the water. 



Although the Wilson petrel has long been known as a common bird 

 of the Atlantic Ocean, especially on the American side, its true dis- 

 tribution, including its breeding place, is but recently acquired 

 knowledge. Alexander Wilson, who first described this species and 

 83969—22 12 



