THE FOOD OF THE OTHER LAND ANIMALS 87 



for instance, eating only the leaves of Arum; this is especially 

 the case, however, in the carnivorous forms because of the 

 widely var>dng habits of their victims. Many birds, including 

 certain African and Malayan owls, certain hawks, some eagles, 

 the pelicans, cormorants, gannets, large herons, large kingfishers 

 and most terns subsist entirely or chiefly upon fish. The 

 secretary bird and certain kites, Hke our swallow-tailed kite, 

 are reptile feeders, preferring snakes; the road-runner, a 

 curious cuckoo, feeds extensively on lizards; the everglade kite 

 and the limpkin live on molluscs. Certain strange crepuscular 

 hawks eat bats, which they swallow whole, with an occasional 

 bird, and vultures feed on carrion. 



Of smaller birds with curious or specialized feeding habits 

 may be mentioned most cuckoos and the caterpillar shrikes, 

 which feed mainly on caterpillars; the crocodile birds, which 

 subsist largely on the parasitic crustaceans which they pick 

 off the gums of crocodiles; some ant-thrushes, which feed 

 more or less extensively on ants, insects also preferred by the 

 ant-shrikes and the ant-eating woodpeckers; and the ox- 

 peckers, which feed largely on the sores on the backs of cattle 

 caused by large fly maggots just beneath the skin. Some 

 birds, like crows and ravens, will eat almost anything either 

 of animal or vegetable nature. 



Sudden increase in animal life of various kinds usually re- 

 sults in the convergence upon it of various birds some of which 

 do not ordinarily subsist upon that particular creature. Ponds 

 in which small fish, especially trout, are raised are haunted 

 by a large assortment of birds, many normally insectivorous, 

 which raid the young fish. Plagues of grasshoppers attract 

 quantities of terns and small gulls, small birds of prey, gaUina- 

 ceous birds, crows, and various finches. Ant armies in the 

 tropics are followed by many birds, a few picking off the ants, 

 but most watching for the insects, small mammals and reptiles 

 fleeing in terror from them. The appearance of the seventeen 

 year cicada is accompanied by a temporary change in the 

 habits of very many of our birds which, ordinarily living in 



