MIGRATION OF BIRDS. 129 



access to the embryos of life in their then state, one 

 season would go far to make the country a desart; 

 and even the birds would be deprived of their summer 

 subsistence for themselves and their young. They are 

 also provided with means by which they can transport 

 themselves, in average states of the weather, without 

 much inconvenience; and thus, while in migration they 

 seek their own immediate comfort, they preserve other 

 races of being. In some of the species, too, they 

 preserve a portion of their own race. It has been 

 mentioned that the young of the swan are unable to 

 migrate the first year ; and of most migratory birds, 

 there are always a few that are unable for the fatigue 

 of migration. If the strong did not go away, the whole 

 of the weak, and in cases like that of the swan, the 

 whole of the young, would perish. After the moulting 

 takes place, in most birds, perhaps in all of them in a 

 state of nature, the paternal instinct ceases to operate ; 

 they feel no more for the brood of that year. It is 

 each for itself individually during the necessity of the 

 winter ; and when the genial warmth of the spring 

 again awakens the more kindly feelings, the objects of 

 those feelings are a new brood. In her march, nature 

 never looks back ; her instinct is fixed on the present, 

 and thus leads to the future, without any reference 

 to that experience which the progress of reason and 

 thought requires. In consequence of this, the strong 

 would take the food from the weak, the active from 

 the feeble, and the full-grown from their offspring, if 

 nature were not true to her purpose, and prompted 

 the powerful to wing their way to regions in which 

 food is more easily to be found, and leave the young 



