THE KOEL AND ITS ALLIES 299 



certained that the young cuckoo turns 

 out the fellow nestlings/' Cuckoos are 

 generally brought up in nests which are 

 too small for their body. It is quite 

 possible that being sardine-packed into a 

 small nest, the nestlings struggle for 

 room, and the cuckoo nestlings being the 

 stronger and generally earlier-born win 

 the day and the others are thrown out. 

 That this is not invariably the case is 

 proved by the fact that in the majority 

 of instances both the cuckoo and the 

 children of the real owner of the nest 

 successfully grow up to be reared and 

 fledged. People have urged that the 

 parasite youngster has a sensitive back, 

 and when its foster-brother comes to sib 

 on it, the former instinctively pushes out 

 the latter. This may be true in the case 

 of Cuculus canorus but, according to 

 Dewar, not true of the Koel. He says, 

 "The young Koel does not eject its fellow 

 nestlings. It is true that many young 

 crows disappeared but in every case this 



