GAME, AQUATIC, AND RAPACIOUS BIRDS. 



25 



eaten, menhaden are prominent, forming an average of 21 per cent 

 of the food. Since these fish are so enormously abundant that their 

 chief economic value is for fertilizer and oil, hundreds of tons of which 

 are made, the number of them consumed by terns is insignificant. 

 Silvery anchovies (Stolephorus) and fresh water minnows (Cyprinidse) 

 compose about 13 

 per cent each. 

 These little fishes 

 swarm in shallow 

 waters and are of 

 no direct value to 

 man. 



The charge that 

 terns prevent the 

 increase of food 

 fishes by eating the 

 small fishes which 

 are their natural 

 food is wholly un- 

 founded, since there 

 is no scarcity in the 

 food supply, but on 

 the contrary a con- 

 stant superabun- 

 dance. In this con- 

 nection we would 

 point out that some 

 largely herbivorous 

 food fishes, such as 

 the buffalo fishes, 

 with whose food 

 supply the terns 

 have very little to 

 do, have alarmingly 

 decreased, just as 

 have some of the 

 carnivorous ones. 

 The cause of re- 

 duction in the num- FIG. 10. -Black tern. 

 ber of food fishes is not chiefly failure of the natural food supply, 

 but, as has been pointed out by experts of the United States Bureau 

 of Fisheries, too close fishing. 



The responsibility for the scarcity of certain food fishes, therefore, 

 can not justly be placed upon the terns, especially since it is shown 

 that a very small proportion of their diet is composed of these fishes. 



497 



