THE NIDIOLOGIST 



sometimes succeeded. Upon throwing the min- 

 nows on the dry parts of the boat's bottom the 

 Terns readily captured them and then the Skim- 

 mers began to try. They would attempt to 

 seize a minnow like the Terns by picking at 

 it straight, but the slightly longer under mandi- 

 ble rendered such attempts abortive, and they 

 soon learned to turn their heads sideways and 

 thus secure a better grip on a small fish. 



" After some practice they learned to pick up 

 enough food, but usually tried to pick up any 

 spot that showed on the bottom of the boat. 



" They readily took bread, meat, lima beans, 

 and cut-up potatoes. Wet bread seemed more 

 palatable, as dry bread was usually refused after 

 being worked between the mandibles for some 

 time. Lima beans they would cut in two, and 

 swallowing one half would then pick up the 

 other. 



" Minnows were invariably swallowed head 

 first. Cut-up fish was chewed for some time, 

 and usually the larger end went down first. If 

 a bone was felt the piece was sometimes re- 

 jected; indeed, the bird had to be very hungry 

 to swallow it. At first I put the young birds 

 after a long sail into a dry boat and afterward 

 added an inch or two of sea water; at once they 

 rushed into the water and not only bathed, but 

 lowering the head until the lower mandible 

 dipped into the water actually drank until they 

 had enough. Aftervvard I kept some for some 

 time from water, and then offering them sea or 

 fresh water in a cigar box found that they only 

 too gladly drank until satisfied. The sound of 

 falling water readily attracted their attention 

 when thirsty, and they would quickly turn and 

 take advantage of the opportunity to drink and 

 bathe. 



" Their previous freedom on a low sandy islet, 

 bounded only by water, led them into some curi- 

 ous actions which I did not at first understand. 

 Putting them into a boat or into a box or alley 

 they invariably at first got into the center and 

 usually turned round a number of times, evi- 

 dently affected by seeing something around to 

 prevent their roving in any direction. How- 

 ever, they soon became reconciled, were riot 

 restless, seldom squawked, and then only when 

 hungry. They readily took to the water and 

 bathed. Upon putting a large one into a bowl 

 of water, he instantly began shaking himself and 

 threw water all over his back, and ceased only 

 when he was thoroughly drenched. Then pla- 

 cing him in the sun he would spend consider- 

 able time in pruning and oiling his feathers. 



"The adults are called ' Flood Gulls ' by the 

 fishermen, evidently because they usually feed 

 on a rising or flood tide. As the tide rises on 

 the extensive flats myriads of minnows keep 

 pace with the rising edge of the water and hunt 



for food. With head to the wind a Skimmer 

 will fly along with its lower mandible in the 

 water. Whether the fish seek the cavity of the 

 bird's mouth for supposed safety, or whether the 

 bird catches the fish by shutting down the upper 

 mandible on them, I am unable to say. 



" I have watched many feeding, but never yet 

 saw one with a fish, or going through the mo- 

 tions of swallowing one. They seem always 

 seeking, dozens of minnows being seen getting 

 out of the way, even jumping out of the water 

 as the birds fly rapidly along skimming the sur- 

 face; and a bird will often fly off in circle, and 

 returning repeat its fishing in the same or nearly 

 the same spot. 



" Sometimes, in shallow water, the point of the 

 lower mandible will strike a shell or other ob- 

 struction, and instantly the head goes under 

 and the body seems to pass on without it. The 

 effects of wearing and injury is often seen on 

 the top of the lower mandible. 



" While watching the birds one will be so for- 

 tunate sometimes as to see it move the upper 

 mandible independently of the lower. Where 

 the upper mandible and the cranium unite is a 

 quite flexible hinge, a contrivance possibly used 

 by the bird when fishing to shut the mouth, and 

 thus swallow without removing the lower jaw 

 from the water. The general rigidity of the 

 lower mandible, lower head and neck when the 

 head is lowered, is well shown in the habits of 

 the young birds when attempting to catch a 

 minnow in the shallow water. The purpose of 

 the flexible upper mandible seemed only too 

 evident at such times. That the birds have this 

 power of moving the upper bill independently 

 of the lower is shown by allowing a hungry bird 

 to seize a finger crosswise in its bill. All the 

 pressure exerted by the bird's bill is then felt 

 where the upper mandible presses into the 

 finger; the lower simply counteracts this pres- 

 sure. The alternate pressure and relaxation of 

 the muscles working the upper mandible will be 

 distinctly felt. 



" When just hatched there is very Httle differ- 

 ence in the length of the mandibles. The length 

 of the lower mandible beyond the upper in a 

 young Skimmer, just flying, is three sixteenths 

 of an inch. 



" Altogether, in its habits the Black Skimmer 

 is an extremely interesting bird, and though it 

 occurs in great numbers on its breeding grounds 

 and is rarely injured by man, the prevention of 

 its breeding by repeated robbery of its eggs is 

 rather to be deplored." ' 



My photographs very well show the growth 

 of the beak in the young of the Skimmer, as 

 well as their general form and pattern of colora- 

 tion. 



R. W. Shufeldt. 



