186 THE POOD OF BIRDS IN INDIA. 



1133. C. bengalensis. Lesser Cotacal. Grasshoppers. F. I. 

 Ill, 244. 



With regard to the Cuckoos, and I here refer to the true para- 

 sitic Cuckoos the Cuculinse, and not to the Koel or the ground 

 Cuckoos, these are generally regarded as being beneficial, the reason 

 being that they are the only, or almost the only, group of birds that 

 will eat hairy caterpillars. We have many references to birds other 

 than the Gu-ckoos eating hairy caterpillars, but these are excep- 

 tions and Cuckoos are the only birds that do so habitually. I 

 have examined a considerable number of different species of birds, 

 and in no other case have I found a bird other than a Cuckoo 

 touch this particular kind of food. Cuckoos, therefore, being the 

 only real bird check we have on hairy caterpillars, which are 

 mostly defoliators, need all the protection we can give them, and 

 should be encouraged as much as is possible. They can only be 

 encouraged in one way, namely, by the encouragement of their 

 hosts. This brings up an interesting, if unimportant point. The 

 hosts of Cuckoos comprise a great number of species of birds, some 

 few of which may possibily be injurious, but the greater proportion 

 are almost certainly beneficial. By parasitising these birds 

 one Cuckoo is produced instead of four or five of the species para- 

 sitised. Is the good a Cuckoo does of more economic importance 

 than the good these other birds should have done ? This we can- 

 not decide until we know all the hosts and what they feed on, i.e. 

 their economic importance. However this may be the Cuckoo 

 is a special check on one particular class of insect, and even if 

 proved not to do so much good as is generally supposed, merits 

 protection from this one cause alone. It is special checks such as 

 these that are of the greatest importance at times, and these are 

 the species of birds to which the economic ornithologist must pay 

 special attention. It is one of his main objects to discriminate 

 such species or genera of birds. 



Of these true cuckoos, besides the genus Cuculus which con- 

 tains but one species common to the plains Cuculus micropterus , 

 we have the following Hierococcyx in which genus occurs the 



