£34 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 
away, 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. 
IT 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 114 
inches in diameter, and 64 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 BirRDsS 
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food is quickly withdrawn, and another is tried.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 
