CONTROL OF INSECT PESTS McATEE 437 



" One has only to read the lists of the food of beneficial species of 

 birds," says Dr. Lefroy, " to get an idea of the immense part they 

 play in reducing insect damage. Nearly all insects have special 

 enemies such as parasites which attack each individuall}^, but which 

 produce alternative abundance and scarcity of each insect; that is, 

 with the natural action of the special checks such as parasites, you 

 get alternative ' waves ' of insect pest and parasite ; this is where 

 the birds' importance is shown ; they are not restricted, they eat 

 many kinds of insects and when a pest has for the time got ahead 

 and is abundant, the birds are there to feed on it just because it is 

 abundant, and because at one time, one is abundant, at another time, 

 another is, and the birds eat them all. To put it figuratively they 

 cut off the tops of the waves and tend to keep them all at a uniform 

 level, none being ever destructively abundant. In my opinion from 

 man's point of view this is the special function in nature of birds 

 and if the bird population is small, outbreaks of insects are fre- 

 quent." *^ 



In other words, entomologists, ornithologists, all of us in fact may 

 agree, Avithout exaggerating the services of birds in the least, that we 

 may look upon them as an ever-present force which automatically 

 tends to check outbreaks, large or small, among the organisms avail- 

 able to them as food. It is a force that should be kept at maximum 

 efficiency by protective measures and which should be taken into 

 consideration and used whenever possible. At the same time we 

 must not neglect to credit with their good services, and t.o protect 

 and adapt to our ends so far as practicable, other insect- destroying 

 vertebrates. Among these certain toads, lizards, shrews, and moles, 

 may in their more restricted spheres, at times approach birds in 

 individual efficiency, and bats may equal them. Various other 

 mammals, reptiles, amphibians, and fishes also have value as insect 

 foes which should not be overlooked. Let us prize them all accord- 

 ing to their deserts, and utilize their services as best we may. 



^'' In Mason, C. W. The Food of Birds in India. Mem. Dept. Agr. India Ent. Ser. 

 Vol. Ill, Jan., 1912, p. 364. 



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