These general principles once realized, a foundation is laid 
on which one may base observations on the peculiarities of flight 
distinguishing different types of birds. 
Most of us, probably, at one time or another, in taking a 
walk through the woods, have been startled, almost out of our wits, 
“‘ whirr ” of wings at our very feet; made by some 
by a sudden 
crouching pheasant, waiting till the very last moment before 
revealing himself, by taking flight. This alarming noise is due 
to the shortness and stiffness of the quill, or flight-feathers. 
With pinions moving with incredible speed, the bird is off like a 
rocket. Not seldom, probably, it owes its life to this ability 
to disconcert its enemies, till it has put a safe distance between 
itself and danger. By way of contrast, let us take the absolutely 
silent, easy movements of the owl, stealing forth in the twilight 
of a summer’s evening, seeking whom he may devour. Here, 
again, we have a meaning in the mode of flight. Here silence 
is more than golden: it means life itself. Nimble-footed, sharp- 
eared mice and rats, must be snatched up before even the breath 
of suspicion can reach them. The uncanny silence of this 
approach is rendered possible, only by what may be called a 
“* muffling ” 
of the wings. For the flight-feathers are not only 
of great breadth, but they are covered, as it were, with velvet- 
pile, the “ barbules” of the wing-quills, which form the agents 
by which the “ web ” of the quill is held together, having their 
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