152 BULLETIN 107, UNITED STATES NATIONAL MUSEUM. 



upper parts are " sooty black," blacker on the head and more sooty 

 on the back; this color extends down on the sides of the head to in- 

 clude the lores and a space below the eyes ; it also includes the sides 

 of the neck and the flanks. There is a small white spot above and 

 another below the eye. The under parts are pure white from the 

 chin to the belly and grayish white posteriorly. 



I have never seen any specimens showing the change from the 

 downy young to the first winter plumage, nor have I been able to detect 

 any difference between young birds during their first winter and 

 adults, except that young birds have slightly smaller bills and a 

 more blackish cast to the dorsal plumage. It has been suggested 

 by several writers that the dusky mottling of the under wing coverts, 

 which is the principal character of Craveri's murrelet, is a sign of 

 immaturity; I have not examined enough material to decide the 

 matter definitely, but am inclined to think that the young of both 

 species will be found to have more dusy in the under wing coverts 

 tlian old birds; this need not necessarily affect, however, the validity 

 of Brachyramphus craveri as a species. 



The seasonal plumage changes of Xantus's murrelet are not con- 

 spicuous. A complete postnuptial molt occurs in August and prob- 

 ably there is an incomplete prcnuptial molt late in the winter. Mr. 

 Adriaan van Kossem (1915) has made some study of the plumages of 

 this and the next species, which has thrown some light on the subject. 



He has illustrated his paper Avith a good photograph showing the 

 seasonal changes in adults of the present species. 



Food. — Mr. Howell contributes the following notes on the food and 

 habits of this murrelet: 



It has been stated that the species vomits a thin yellow oil when handled, 

 after the manner of the petrels, but from a hundred or more birds which I have 

 had in the hand not one has shown any inclination to do this, nor has their 

 stomach contained any oily substance, but only a clotted greenish slime and very- 

 little of that. This was no doubt some kind of sea vegetation mixed with saliva. 

 They must dive for their food, and I believe that a very small proportion of 

 their fare, if any, consists of fish, for their throats are not capable of enough 

 expansion to indicate that they are fish eaters. Probably they are partial to all 

 forms of small Crustacea and minute forms of sea life which are so plentiful 

 among the weeds and rocks. 



Behavior. — In flight the wing beats are very rapid, almost a buzz, and they 

 are capable of great speed. When attacked by a duck hawk while flying they 

 will suffer themselves to be caught rather than take to the water. Shortly 

 after dark large numbers of the birds make their way into the coves and shallow 

 water near the islands. From then until dawn they can be heard giving their 

 characteristic cry, which can best be described as a shrill slow twitter, about 

 four notes to the second. At night, especially when hunting a nesting site, 

 they are sometimes attracted by a light on shore. Doubtless they make several 

 trips to the burrows throughout the night. During the day they keep well out 

 to sea and are usually to be foimd in pairs or family parties. When pressed 

 too closely they rise to the wind and fly into the distance, but refuse to dive 

 unless wounded. 



