20 



sleeping sickness of Central Africa, rat-fleas plague, lice typhus fever, etc., 

 etc. There is no longer any doubt as to the inter-relationships that exist in 

 this part of the web of life. 



Again, fishes furnish another link in the chain connecting mosquitoes 

 and malaria. As is well known certain fishes feed upon mosquito larvae, 

 and in many districts are undoubtedly instrumental in regulating the amount 

 of malaria. It is believed that the presence of the small fish called " Millions" 

 in Barbados is the reason why that Island is so free from malaria. 



Insects and Birds. 



Facts which convince even the most sceptical are accumulating regard- 

 ing the valuable role played by birds in the control of noxious insects. 

 Studies of bird diets prove conclusively that the majority of our common 

 birds feed mainly upon insects. Forbes of Illinois states after a careful 

 study of the contents of the stomachs of birds that about two-thirds of 

 the food of birds consists of insects. Well-informed writers tell us that with- 

 out birds the e0.rth would be uninhabitable after six years, and yet man in 

 his ignorance is constantly destroying these valuable friends, simply because 

 he finds that they levy an insignificant toll on his fruits and grains. It is 

 possible tha.t we would be better oft" if certain birds were greatly reduced 

 in numbers, but of this we are not absolutely certain, for the web of life 

 is most complex, and no person knows how far-reaching the results would 

 be. 



Aside from the fact that birds aid very materially in reducing the num- 

 bers of insects when they come as scourges, it is very important to remember 

 that birds nip many incipient scourges in the bud. Their mobility and varied 

 character and habits enable them to move rapidly from place to place and 

 thus maintain the balance of nature which man is always tending to upset. 

 Even in wild nature the balance is never quite complete; at best the equili- 

 brium is unstable. 



"It is very interesting that the two great classes of successful flierS 

 should be, in the wide economics of Nature, fitted against one another, 

 wings against wings, freeman against freeman, invertebrate against ver- 

 tebrate, "little brain" against "big brain," "instinct" against "intelli- 

 gence." Practically this is the most important conflict of classes that the 

 world knows." — (Thomson). 



