﻿FOOD OP AMERICAN PHALAROPES, AVOCETS, AND STILTS 5 



One hundred and fifty-five stomachs examined in determining the 

 economic status of the northern phalarope are representative of the 

 food of this bird, save when it is absent from the United States in 

 winter. The material available is distributed rather evenly throughout 

 the months from May to October, inclusive. That representing the 

 'ood during the breeding season comes from Alaska, but the remainder 

 >^as taken through the Northern States and California. Animal food 

 forms 97.2 per cent, and seeds and some miscellaneous vegetable mat- 

 ter make up the remainder (2.8 per cent). 



ANIMAL FOOD 



Crustacea. — In the series of stomachs examined crustaceans come 

 to 9.3 per cent, and are represented in every month. Eighteen birds 

 taken in September had eaten these animals to the extent of one-fourth 

 .. their food, but at other seasons the number taken is less. When 

 phalaropes are feeding at sea, no doubt crustaceans are eaten in much 

 greater quantity than here indicated. Amphipods, fragments of 

 which were found in 10 stomachs, form an easily obtained food, espe- 

 cially in northern waters. The curious winter eggs of another group 

 of crustaceans (Daphniidse) were found in two individuals. These 

 eggs resemble a small seed pod with two black spots on either side. 

 They must be present in abundance in some Alaskan localities, as 

 they are eaten frequently by small shorebirds. 



l^rine shrimps {Artemia fertilis) were identified in eight birds taken 

 on Great Salt Lake, Utah. These curious animals, less than an inch 



\ length, abound in the concentrated brine of lakes in the Great 

 Basin, being one of the few creatures that have become adapted to 

 water so strongly saline. In Great Salt Lake these shrimps swarm 

 in the shallow bays. The bodies of brine shrimps are soft and friable 

 with no hard parts to resist digestion. Their detection in stomach 

 examination is difficult, as the diffuse eye-spots or eggs in the case of 



"ceding females, are the only characters that may be recognized. 

 In the field it was observed that northern phalaropes were feeding 

 extensively upon brine shrimps, and stomachs of those killed bear 

 out this observation. It is certain that these crustaceans are an at- 

 tractive food and that large numbers are eaten. Other crustaceans 

 than those previously mentioned, in two instances isopods (Cymo- 

 thoidea), were found in four other stomachs. 



Hemiptera. — True bugs are an important source of food, amounting 

 to 3L8 per cent of the whole. The bulk of them are the widely dis- 

 tributed water-boatmen (Corixidae), eaten by 42 birds. Back-swim- 

 mers (Notoncctidse) were eaten by 5 birds, and miscellaneous forms, 

 mainly unidentified, by 12. The favored species in this order of 

 insects are those of aquatic habit. 



Coleoptera. — Beetles were found abundantly in the examination of 

 these stomachs and totaled ]6.5 per cent of the food. Species that 

 live in the water or are found on muddy shores arc well represented. 

 Ground beetles CCarabida^J were found 12 times. Crawling water- 

 beetles (JfaliplidaO, small species occurring in submerged vegetation, 

 were taken 1(J times. Four species were definitely identified. The 

 predacious diving beetles (Dytiscidu)) seem to be especially favored, 

 adult forms being founfl in 20 stomachs and larval in 14. Water- 

 scavenger beetles CliydropliihdaO were found in 19 stomachs and 

 their larvje in 0. Unidentified af[uati(^ beetles occurred 14 times. 



