i34 THE POPULAR SCIENCE MONTHLY 



wings often interlocked,, during their long imprisonment in a dark, 

 subterranean chamber. When, after a good rest in this position, they 

 were brought to right-about-face, two immediately moved backward a 

 few steps, and came to rest again (Figs. 31 and 32). Move around 

 them in circle, and not a head is turned; make a pass of the hand sud- 

 denly towards them, and sometimes there is a slight backward move- 

 ment, but sometimes there is none; reverse again with heads turned 

 awa} r , and two turn part way around, one of which repeats the move- 

 ment when repeatedly reversed. If placed on their backs, they will 

 slowly right themselves, though if in the nest-hole they were sometimes 

 contented with this position for a longer time. 



I am now convinced that the earlier conclusion was correct, and 

 that the peculiar actions described are due to habit, learned under- 

 ground, and in relation to getting their food, although I was probably 

 in error in supposing that their instinct of fear was ordinarily delayed 

 until they were ready to leave the tunnel. When such birds are handled 

 daily there can be little doubt that this instinct is liable to be checked. 

 The arched chamber of sand in which these kingfishers lay was 11^ 

 inches in diameter, and 6^ inches high, while the tunnel leading to it 

 had a 3-inch bore. Its temperature stood at 77° F., and was seven 

 degrees cooler than that of the air outside. Since these five birds were 

 each about six inches long it is evident that they were closely packed, 

 and that once in the tunnel, no turning movement would be possible, 

 any more than for the adult which after feeding always backs out of 

 the hole. Now we have earlier noticed a tendency among the older 

 young to crawl down the passageway, and meet the parent at the mouth, 

 but that they are hustled back and presumably fed at the nest, hence 

 the probable association between walking backwards and getting food, 

 and hence the curious habit displayed by these birds when they are 

 taken from the ground. 



III. Intelligence in Adult Birds 



There seems to be little intelligence displayed by birds in regard to 

 the quantity of food served at the nest. What one of the altricious 

 kinds really does in effect is to " test " the reaction of the throat of its 

 nestling, and to await the response. If this is not forthcoming the 

 food is quickly withdrawn, and another is tried. The most responsive 

 bird gets the food, and there is no distribution on any other basis than 

 this. The same bird may thus be fed twice or even three times in 

 succession, the strongest usually getting the most, and the amount 

 which it can take being reflexly determined by the gullet. 



On the other hand, intelligence is certainly shown in the kind of 

 food served, and in the treatment which it often receives. Thus a gull 



