THE IMMORTAL NIGHTINGALE 241 



by as possible. It is probably harder for the nightin- 

 gale to go a mile away from his true home, the very 

 spot where he was hatched and reared, than to fly 

 away thousands of miles to his wintering-place in the 

 autumn. The bird is exceedingly reluctant to leave 

 his home, but if the annual increase was greater, a 

 third greater let us say, more and more birds would 

 be compelled to go further afield. They would go 

 slowly, clinging to unsuitable places near their cradle- 

 home rather than go far, but the continual pressure 

 would tell in the end; the best places within the 

 nightingale country, the ten thousand oak and hazel 

 copses and thickets which are now untenanted, would 

 be gradually occupied, and eventually the limits 

 would be enlarged. That they cannot be extended 

 artificially we know from the experiments in Scotland 

 of Sir John Sinclair and of others in the north of 

 England, who procured nightingales' eggs and had 

 them placed in robins' nests. The young were hatched 

 and safely reared, and, as was expected, disappeared 

 in the autumn, but they never returned. We can 

 only assume that the "inherited memory" of its 

 true home, which was not Scotland nor Yorkshire, 

 but where the egg was laid, was in every bird's brain 

 from the shell, that if it ever survived to return from 

 its far journey it came faithfully back to the very 

 spot where the egg had been taken. 



That man's persecution tells seriously on the 



species may be seen from what has happened on 



the Continent, even in countries where the hateful 



custom of eating nightingales with all small birds is 



Q 



