BIRDS AS AUTOMATA 109 



doing actually attract attention to the eggs. This action 

 is purely instinctive, and is perpetuated and strengthened 

 by natural selection because it is beneficial to the race. 



We have seen how at the nesting season all a bird's 

 normal actions and instincts are subordinated to those of 

 incubation. It is therefore but reasonable to suppose 

 the incubating bird to be in a very peculiar and excitable 

 state, a state bordering on insanity. 



A bird in this condition might be expected to go into 

 something resembling convulsions on the approach of 

 an enemy, and, provided its acts under such circum- 

 stances tended to help the offspring to escape, and were 

 at the same time not sufficiently acute to cause the 

 mother bird to fall a victim to the enemy, natural 

 selection would tend to perpetuate and fix such actions. 



Want of space prevents further dilation upon this 

 fascinating subject. 



To sum up the conclusions I desire to emphasise. A 

 bird has during the greater part of its life only to look 

 after itself, and the more intelligent it be the better will 

 it do this, hence natural selection tends to increase the 

 intelligence of birds. But, at certain seasons, it becomes 

 all-important to the species that the adults should attend 

 to their young, even at risk to themselves. To secure 

 this Nature has placed inside birds a force, dormant at 

 most times, which at periodic intervals completely over- 

 rides all normal instincts, a force which compels parent 

 birds to rivet their attention on the nest and its contents. 

 Thus the sudden conversion of birds into automata is a 

 necessity, not a mere whim of Dame Nature. The 

 instinct is not of very long duration ; for as soon as the 



