316 BULLETIN 113, UNITED STATES. NATIONAL. MUSEUM 



The juvenal plumage is -handsomely and boldly marked; the upper 

 half of the head is "pale Ochraceous salmon" colored and the 

 feathers of the back, scapulars, and wing-coverts are broadly tipped 

 and edged with the same color, each feather being centrally dusky. 

 These edgings, which are fully a quarter of an inch broad on the 

 scapulars,, soon fade out to white and wear away, leaving a dingy 

 mottled effect on the upper parts. During the winter some progress 

 is made toward maturity,* and at the first prenuptial molt, "which is 

 complete, young birds become practically indistinguishable from 

 adults. Adults have two complete molts each, year, a prenuptial 

 in February anil March and a postnuptial in August and September. 

 The adult winter plumage is similar, to the nuptial,: but the upper 

 parts are browner, and there is a more or less distinct nuchal collar 

 of whitish feathers. 



Food. — The food of the black skimmer consists mainly of small 

 fish, and to some extent shrimps and other small crustaceans. It feeds 

 largely on the wing by skimming close ;to the smooth water, cutting 

 with its long, rigid lower mandible the surface, from which it scoops 

 into the small mouth the animal food to be found there. : The upper 

 mandible, which is movable, can plainly be seen to close down upon 

 any morsel of food which is picked up. That it feeds largely at n^ght 

 everyone knows who has lain at anchor among the shoals of the 

 South Attafitic coast and seen the shadowy' forms flitting by in the 

 gloom, but it does not do so exclusively, as has been stated. T have 

 frequently seen it feeding in broad daylight, and think that it' is 

 more influenced by the tides than by anything else, for these at 

 certain stages make its food more accessible. It is never seen to dive 

 for its food, and its bill is n6t adapted for picking it up on the shore. 



Mr. Arthur seems to have discovered another method of feeding, 

 about which he writes me : 



Afcdording to my observations the birds seek shallow^ -water of not over 3 

 ihches depth and pick up minnows and other small fish by a direct forward 

 movement of the head and bill, in no way differing' from ; a chick picking up a 

 worm on dry land. Skimmers I havte had in captivity, where fish was thrown 

 to them on a hard surface, were compelled to turn th-eir- heads sideways to 

 pick up the fish ; but the skimmers I had under observation were working on a 

 soft mud bottom, and 1 did not observe a single instance of the head being turned 

 sideways to pick up the food. It was very 1 noticeable at this time that while 

 some of the birds were fishing in the shallow water " other skimmers would 

 come skimming over the water in the characteristic manner, but when they 

 came to a stop they, too, began wading around and fishing in the manner I have 

 just described^ . .,, . . -..,.■■<•- 



' Stomachs collected .and sent to the United States Bureau' of Biological Survey 

 for identification of contents very unfortunately proved to be empty, and I 

 have no positive data from this source aS to what constituted the skimmer's 

 food at this time of the year, but on July 5, while on Alexander Island, there 

 occurred an unusual incident, in which a fish, a Forster tern, and a birdologist 

 all figured. Making my way along a stretch of sandy beach I noted a skimmer 



