THE CYCLE OF LIFE 429 



After brooding there is the labour of feeding the young, 

 which often taxes to the utmost the energies of both parents. 

 Miles away from the Bird-Berg, where tens of thousands of 

 guillemots lay their eggs on the ledges of the cliffs, there 

 is a ' bank ' where sand-eels abound, and it is interesting 

 to lie in a boat and see the constant double stream of birds 

 passing overhead, all those returning to the cliffs having 

 a glistening fish in their mouth. We do not know which 

 most to wonder at, the appetite of the youngsters, the 

 indefatigableness of the parents, or the supply of sand- 

 eels. 



We have already referred to the story of the hornbill. 

 The mother-bird nests in a hole in a tree, and is 

 imprisoned by a doorway of resinous material, big 

 enough to let the male bird's bill in, but small enough 

 to keep enemies out. On the male devolves the task 

 of procuring food for his immured mate, and afterwards 

 for his offspring also. After three weeks of it, he is often 

 worn quite thin, and sometimes he actually succumbs to 

 his other-regarding exertions before he is rejoined by 

 the female bird. He has to do it and it is said that an 

 unrelated male will attend to a widowed bird so 

 that we may not be warranted in using big words like 

 altruism in appreciating his behaviour. But no amount 

 of scrupulosity can disguise the fact that his expenditure 

 of energy is not for himself. 



After the labour of feeding, comes the fine art of 

 education, for the young bird has always a great deal 

 to learn. Experiments in artificial incubation have shown 

 conclusively that the young bird is not rich in inborn 

 knowledge. The chick artificially hatched, with the aid of 

 an inanimate foster-mother, has no instinctive recognition 



