SEMIPALMATED SANDPIPER ' 249 



cent. Fly pupae figure largely iu two stomachs, forming 21.G6 per cent of 

 the total, and snails (Planorbis sp.) 13 per cent, while miscellaneous animal 

 matter amounts to 12.50 per cent. The small quantity of vegetable matter 

 present was rubbish. The numbers of Diptera eaten speak well for this 

 sandpiper. 



Preble and McAtee (1923) found in the stomach of a bird shot in 

 the Pribilof Islands " remains of the beach beetle {Aegialites cali- 

 fornicus), 10 per cent; fragments of small flies (Diptera), 85 per 

 cent; and two seeds (not identified), 5 per cent." 



Arthur H. Howell (1924) says, " Two stomachs of this birds from 

 Alabama contained the remains of small mollusks, fly larvae and 

 beetles. This species is known to feed on marine worms and 

 mosquitoes." 



Behavior. — Semipalmated sandpipers are fascinating birds to 

 watch. When feeding on the beaches, they run along in a scattered 

 flock just above the wave line, retreating rapidly as the wave ad- 

 vances, but sometimes being forced to flutter above it, all the time 

 eagerly seeking for choice morsels. With head down, not held up as 

 is the case with its companions the semipalmated plovers, it runs 

 along dabbling here and there irregularly, and occasionally probing 

 with its bill in the sand. These probings are not so deep nor so 

 systematic as those of the sanderling, which makes a series of six to 

 a dozen holes in succession throwing up the sand on either side. 

 In its greediness the semipalmated sandpiper sometimes attempts to 

 swallow too large a morsel for its small round mouth, which is much 

 out of proportion to the stretch of the end of the bill, and many 

 shakings of the head are needed to get a large morsel past the stick- 

 ing point. I have seen one try several times to swallow a large 

 beach flea {Talorchestia megato phthalma) , and then fly off with it 

 in its bill. 



On a rocky shore I have seen them hunting for insects at high 

 tide on the smooth rocks, and at low tide, running among the rocks 

 covered with seaweed (Fucus vesiculsus) and on the floating weed, 

 fluttering their wings from time to time to keep from sinking. Here 

 they find plenty of food in the small mollusks and crustaceans, 

 Littorina and Gammar'us. On an August day on the coast of Maine 

 I saw one searching about on floating rockweed several miles from 

 land. Shore birds doubtless often rest in this way in their long 

 journeys over sea. 



In flight, semipalmated sandpipers in flocks, large and small, often 

 move as one bird, twisting and turning with military precision, 

 alternately displaying their light breasts and darker backs — flashing 

 white and then almost disappearing. The method which enables 

 shore birds, or, indeed, any flocking bird, to accomplish these evolu- 

 tions is obscure. In the case of the semipalmated sandpiper these 



