LIFE HISTORIES QF NORTH AMERICAN, PETRELS AND, PELICANS. 161 



Eggs. — The single egg of the ashy petrel is much like that of the 

 other small petrels. It is dull white or c^reamy, white in color and 

 either spotless or faintly wreathed with a circle of very fine reddish 

 dots near the larger end. The measurements of 54 eggs, in various 

 collections, average 29.7 by 22.8 millimeters; the eggs shoAving the 

 four extremes measure 31.8 by 22.5, 30.3 by 24.4, 27 by 22.5, and 

 29 ijy 21 millimeters. 



Young. — Mr. W. Otto Emerson's notes state that the young do not 

 leave the nest until they are fully feathered and that they are fed on 

 " small marine insects," which are probably regurgitated by the 

 parents in semidigested form. Specimens of downy young, collected 

 on the Farallon Islands on September 15, 1911, are covered with long, 

 soft down, except on the naked chin and throat ; the down varies in 

 color from "fuscous" to "hair brown." The plumage appears first 

 ,on the wings, back, and head, the down disappearing last on the 

 breast and belly, after the wings are fully developed. The first 

 plumage acquired is practically indistinguishable from that of the 

 adult, so there is no noticeable sequence of plumages to maturity. 



Food. — Very little is known about the food of this species, but Mr. 

 Barlow (1894a) makes the following rather unsatisfactory remark: 

 "The food of the petrel necessarily consists of fish or small shell- 

 fish, with possibly a little marine algae by way of desert, but unfor- 

 tunately no stomachs were examined." 



Behavior. — ^Mr. Henry B. Kaeding (1903) describes the flight of 

 this species as follows: 



When flying about in the dim light the petrels resemble bats. Their flight is 

 fluttering and zigzag and they frequently flit by the head of the watcher close 

 enough for him to feel the wind of their wings. Often they run into the glass 

 around the big light, or into the telephone wires that stretch from the lighthouse 

 to the keepers' houses and the siren, and terminate their erratic careers then 

 and there. Small, dainty, and velvety, they are the prettiest little birds imagi- 

 nable, and would be perfect were it not for their habit of vomiting oil over 

 everything when 'disturbed. 



The same writer says of its notes : 



These petrels, like others of their kind that' nest farther south, are nocturnal 

 in their habits during the breeding season, and seem to exchange places shortly 

 after dark, the incoming birds replacing the mate on the nest after an exchange 

 of ; courtesies and a chat over the day's happenings. These conversations are 

 carried on in a queer little sing-song twitter, regularly punctuated with a gasp 

 that resembles the exhaust of a Lilliputian engine. This twitter is character- 

 istic of all petrels, varying with the species, and has been admirably described 

 •by Mr. A. W. Anthony. 



Mr. Barlow (1894a) says the note was "a squeaky note uttered 

 rapidly and in a low chuckling tone, and was prolonged for several 

 seconds." 



