NATURAL HISTORY OF SOUTH AFRICA 



thrushes, starlings, weavers, and warblers, brought 

 food 150 times in a day of sixteen hours. On calm, 

 warm, cloudy days, when insects were especially active, 

 the parents visited the nest as often as 320 times. 



An examination of the crops of the young revealed 

 the fact that for every beneficial insect there were ninety- 

 five noxious ones. It is by no means good enough to 



The masses of Insects' Eggs on twigs are picked oft 

 and eaten by birds. 



strictly preserve certain kinds of birds and leave others 

 without any measure of protection, for the reason that 

 each species of bird has its likes and dislikes in regard 

 to food. Some birds feed their young on certain 

 species of insects which another bird will pass by as 

 unpalatable. For instance, I have observed the fiskal 

 fly-catcher (Sigelus silens) feed its young on a certain 

 hairy caterpillar that no other bird would touch. It 

 will therefore be realised that it is not sufficient to 

 protect the purely insectivorous birds only. An army 

 is composed of many regiments, and each has its 



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