14 INTRODUCTION. 
Much has been written upon the instincts of birds, 
and a great deal of this would have been better had 
the authors treated of intelligence instead. Birds, 
of course, have instincts; so have men; but the 
former are not guided by them blindly, as so com- 
monly was taught in the not very distant past. In- 
stead, they depend upon the exercise of a faculty 
which in ourselves we call “ common sense.” 
Nuttall, in the Introduction to his “ Manual of the 
Ornithology of the United States and Canada,” says, 
‘‘In respect to the habits of birds, we well know that, 
like quadrupeds, they possess, though in a lower 
degree, the capacity for a certain measure of what may 
be termed education, or the power of adding to their 
stock of invariable habits the additional traits of an 
inferior degree of reason.” This is both true and not 
true. They are, I hold, at least the equals of quadru- 
peds, and the “degree of reason” is not so very inferior. 
Compare, without prejudice or preconceived notion, 
a mouse and a sparrow, an opossum and a crow, a 
weasel and a hawk, and invariably you will find that 
the feathered is the superior of the furred creature 
in just this very point of what I call common sense, 
or, more properly speaking, cunning. The mammal 
when surprised is most frequently confused, and if 
the simplest methods of escape fail, it falls a victim, 
but a bird is equal in more than one way to the occa- 
sion, and by pure brain-power escapes when a merely 
physical effort would not avail. Birds have not been 
sufficiently studied in this respect. We have been 
content to determine the ordinary events of their 
daily lives, and forget that with them, as with our- 
