it will pursue a straight course, with arrow-like speed. Yet 
its cousin, the jack-snipe, never twists. 
Why does the woodcock invariably drop after a charge of 
shot, even though not a pellet has touched it, while a snipe 
pursues its way? These differences are not merely differ- 
ences of “ habit” : they indicate subtle differences in nervous 
response to the same kind of stimulus, and in structural 
details yet to be unravelled. 
Some day the cinematograph will reveal to us all the 
phases of flight and the movements to which they are due. 
Even now, thanks to the modern camera, we have learned a 
great deal. We have learned, for example, that the flight 
of a bird is not effected merely by rapid up and down move- 
ments of the fully extended wings, or with flexed wings— 
that is to say, half-closed, as in “‘ gliding ”’ flight when a bird 
is descending, or in the swoop of, say, the sparrowhawk. 
Only in one of these two positions do we ever seem to see the 
wings when we have to trust to our eyes alone, as the bird 
hurries past us. The impression that we have seen aright 
is confirmed when we stand on the deck of a steamer, and 
watch the gulls following in its wake. For incredibly long 
distances they will travel without a perceptible wing-beat. 
The albatross is the finest of all performers in regard to this 
kind of flight, which is due, apparently, to air currents created 
by stiff breezes, or gales. Some birds seem to make their 
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