WHAT DO ANIMALS KNOW? 
dead leaves when in a hedge-row or a bramble-bush, 
in each case thus rendering the nest very difficult of 
detection because it harmonizes so perfectly with its 
surroundings, and the writer wonders if this har- 
mony is the result of accident or of design. He is 
inclined to think that it is unpremeditated, as I my- 
self do. The bird uses the material nearest to hand. 
Another case, which this same writer gives at 
second-hand, of a bird recognizing the value of pro- 
tective coloration, is not credible. A friend of his 
told him that he had once visited a colony of terns 
“on an island where the natural breeding accom- 
modation was so limited that many of them had 
conveyed patches of pebbles on to the grass and laid 
their eggs thereon.” 
Here is the same difficulty we have encountered 
before — one more step of reasoning than the bird 
is capable of. As a deduction from observed facts, 
a bird, of course, knows nothing about protective 
coloring; its wisdom in this respect is the wisdom 
of Nature, and Nature in animal life never acts with 
this kind of foresight. A bird may exercise some 
choice about the background of its nest, but it will 
not make both nest and background. 
Nature learns by endless experiment. Through a 
long and expensive process of natural selection she 
seems to have brought the color of certain animals 
and the color of their environment pretty close 
together, the better to hide the animals from their 
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