NATURAL HISTORY OF SOUTH AFRICA 



be fed by the parents until they are fully fledged and 

 have learned how to find and capture their own food. 

 The young of the secretary bird remain in the nest for 

 nearly six months until fully feathered, while those of 

 the English sparrow are out in about a week. 



A nestling bird will eat its own weight of food 

 in twenty-four hours. Some kinds eat double their 

 weight in the same period. The young of the smaller 

 species of birds, such, for instance, as robins, warblers, 

 thrushes, etc., will eat 150 caterpillars, each 1 inch 

 long, in twelve hours, and then will be greedy for more. 

 A brood of birds consists in most instances of from 

 three to five youngsters. We will take four as the 

 average. If one young bird eats 1 50 caterpillars and 

 other kinds of insect pests in the course of one day, 

 the four will dispose of 600 daily. Add to this another 

 100 for the parents' sustenance, and we have 700 

 insect pests destroyed daily for about two months. 

 Therefore from the day the young hatch until they 

 are able to fend for themselves, a single family of 

 birds will destroy 42,000 insects. If these are true 

 insectivorous birds they will continue their daily war on 

 our insect enemies. Should they be of the seed-eating 

 kind, they will also continue to feed largely on various 

 forms of insects and allied noxious kinds of life, 

 although their staple food will consist of seeds. It 

 consequently rests with the individual farmer to use 

 his discretion. If the birds are attacking his corn in 

 phenomenal numbers he may be compelled to reduce 

 them to normal limits. If they, however, are not too 

 numerous it will pay him infinitely better to hire 



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