22 
NEW HAMPSHIRE NATURE STUDIES 
more of the history written in the snow, his eyes catch the faint 
impression of a pair of wing-tips near where the trail ends, and 
instantly he recognizes that a tragedy has been enacted.” 
The commoner hawks are also beneficial, destroying great 
numbers of mice and insects. It is all right to trap or shoot a hawk 
or owl that is known to rob the poultry yard, but it is a mistake to 
destroy all sorts of these birds indiscriminately. 
Adaptation of Structure to Functions 
It would be a pity to make this study of the relation ot birds to 
insects and other animals without calling attention at the same time 
to the adaptation of the structure of each bird to the feeding habits 
which so largely determine its mode of life. There is not space 
here for the full discussion of this subject I should like to give, but 
a few lines of observation may be briefly indicated. 
The bird takes its food with or in its beak : Notice the strong, 
Head of Shrike 
solid beak of the 
robin, the crow, and 
other birds that get 
food on the ground ; 
the chisel-like beak 
of the woodpeckers ; 
the very wide beak 
of the swallows, the 
night hawk, and the 
whippoorwill ; the 
flat beak of the fly- 
catchers ; the point- 
ed beak of the war- 
blers ; the long, 
probing beak of the woodcock, plovers, anti sandpipeis, the speai- 
like beak of the herons and bitterns; the wide, flat beak of the 
ducks, and the hooked beak of the hawks and owls. Each of these 
is well adapted to getting the sort of food the bird requires. 
The manner and habits of flight of the bird are largely deter- 
mined by the nature of its food : Notice the comparatively labored 
flight of the robin, crow, and other birds with large bodies; the 
quick, undulatory motion of the woodpeckers; the short, strong 
flights of the flycatchers; the easy, light-bodied flight of the swal- 
