WILSON" PHALAEOPE 33 



in shallow water. It does, however, adopt the whirling tactics of 

 the others occasionally, concerning which Mr. Dawson (1923) says: 



Instead of swinging from side to side with a rhythmical motion, as do the 

 reds and northerns, the Wilson whirls all the way around. Moreover, he 

 keeps on whirling, and though he pauses for the fraction of a second to 

 inspect his chances, he goes on and on again like an industrious, mad clock. 

 One bird which I had under the binoculars turned completely around 247 

 times in one spot, without stopping save for instantaneous dabs at prey. 

 These dabs were directed forward or backward, i. e., with or against the 

 direction of the body motion. A single gyration normally contains two such 

 minute pauses, accompanied by a hitching motion of the head ; and these are 

 evidently the periods of maximum attention, since they are followed by, or 

 rather flow into, the prey stroke, if game is sighted. " Game " is not always 

 abundant nor certain, and I have seen a bird whirl a dozen times without a 

 single stroke. 



The method of feeding on mud flats or in shallow water is well 

 described by Koland C. Ross (1924), as follows: 



When feeding along the shallows with least, western, and red-backed sand- 

 pipers, they differed from them not only in size and color, but in their habit 

 of steady, energetic walking and the constant " side sweeping " with the bill. 

 Occasionally they picked objects from the surface with their needle bills, but 

 this was not very actively pursued. In deeper water they fed among the 

 northern phalaropes, knots, and dowitchers, wading along until they swam 

 in places. However, they were able to wade where the northern swam. At 

 such depths they feed with the head clear under and the energy of the feeding 

 operation was indicated by the motion of the tail. They commonly walked 

 steadily back and forth through the deeper sections of the ponds, and in such 

 deep places they moved as headless bodies, evidently feeding as usual in the 

 surface mud. From the vigorous side moves of the tail it would seem they 

 were feeding in their usual manner as well ; that is, " side sweeping." When 

 the birds were standing to feed in the deeper places the tail was again much 

 in evidence, and indicated the manner of feeding. This would seem to be a 

 probing motion performed with some rapid vibration which was communi- 

 cated to the tail as a series of quivers. It is rather a droll sight, and arrest- 

 ing as well, to see a certain area marked out by headless gray bodies buried in 

 the water up to the bend of the wing, the vibrating tail indicating the vigorous 

 operations being carried on down below. It seemed their best feeding was in 

 the deeper waters. 



The feeding habits of this and the other phalaropes are almost 

 wholly beneficial. They live very largely on the larvae of mos- 

 quitoes. They also eat crane-fly larvae, which are often very de- 

 structive in grass lands and wheat fields. Predaceous diving beetles, 

 which are a nuisance in fish hatcheries, are eaten by them. Dr. 

 Alexander Wetmore's (1925) analysis of the contents of 106 stomachs 

 showed that the food of the Wilson phalarope is mainly insects, 

 of which various flies made up 43.1 per cent, aquatic bugs 24.4 per 

 cent and beetles 20.1 per cent. The remainder of the food included 

 brine shrimps, amphipods, eggs of water fleas, and seeds of various 

 aquatic plants. 



