WAYS OF NATURE 
of paper, and dry grass. After the third day the site 
on the branch was bare, the wind having swept 
away every vestige of the nest. As I passed beneath 
the tree I saw the thrush standing where the nest 
had been, apparently in deep thought. A few days 
afterward I looked again, and the nest was com- 
pleted. The bird had got ahead of the wind at 
last. The nesting-instinct had triumphed over the 
weather. 
Take the case of the little yellow warbler when 
the cowbird drops her egg into its nest — does any- 
thing like a process of thought or reflection pass in 
the bird’s mind then? The warbler is much dis- 
turbed when she discovers the strange egg, and her 
mate appears to share her agitation. Then after a 
time, and after the two have apparently considered 
the matter together, the mother bird proceeds to 
bury the egg by building another nest on top of the 
oldone. If another cowbird’s egg is dropped in this 
one, she will proceed to get rid of this in the same 
way. This all looks very like reflection. But let us 
consider the matter a moment. This thing between 
the cowbird and the warbler has been going on for 
innumerable generations. The yellow warbler 
seems to be the favorite host of this parasite, and 
something like a special instinct may have grown up 
in the warbler with reference to this strange egg. 
The bird reacts, as the psychologists say, at sight of 
it, then she proceeds to dispose of it in the way 
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