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THE POPULAR SCIENCE MONTHLY 



Fig. 12. Gdll Regurgitating, and the young seizing the shrimp, squid, or fish as 



they leave the mouth or fall to the ground. Type of indirect 



feeding by regurgitation. 



ject of the law being not merely to preserve the game, but to signalize 

 the sanctity of this instinct. 



The brooding instinct rises like a fever, reaches a culmination at 

 the time the eggs hatch or shortly after, and then rapidly subsides. At 

 the same time there is a corresponding depression of fear, which re- 

 turns with the waning of the brooding impulse. Thereafter brooding 

 becomes more intermittent, being determined in some degree by the 

 intensity of light, and weather conditions, with the difference that 

 fear is now in the ascendent, and the element of intelligence, at the 

 plane of association at least, is not lacking. At its first manifestation 

 it affords a beautiful illustration of a pure instinct, adapted to the 

 preservation of the offspring, though attended at times by what blind 

 and costly sacrifice of life can well be imagined. 



At the command of the brooding instinct, or at the sight or touch 

 of the eggs, and later of the young, the whole nature of the bird is 

 quickly changed. In his experiments with noddy and sooty terns, 

 Watson 4 found that while neither bird recognized its own egg, the 

 habits of a laying noddy could be almost immediately changed into 

 those of a " sitter " by placing an egg in its nest. Before the appear- 

 ance of the egg, this bird is shy and easily disturbed, but contact with 

 an egg, and an artificial one at that, seemed to change its disposition 



1 Watson, John B., "The Behavior of Noddy and Sooty Terns," Pub. No. 

 103, Carnegie Institution of Washington, p. 223, Washington, 1909. 



