USES OF THE WING 
105 
geon and dentist; but spears, awls, chisels, picks, hooks, crackers, 
trowels, needles, scoops and strainers are also represented in the bird’s 
equipment. Primarily these instruments or weapons are designed to 
secure food for the adult and to feed its young, but the bill is also of 
service in preening, 
in gathering and 
placing nesting ma- 
terial or excavating 
nesting - sites, and 
as a weapon of at- 
tack or defence in 
the usually harmless 
struggles of birds. Woodpeckers use it as a drumstick. Owls rattle 
their mandibles threateningly, and Pelicans snap theirs in loud defiance. 
With some birds, the bill is the seat of some special growth or color 
during the breeding season. The White Pelican then wears a keel- 
like knob on the upper mandible, and the bills of Auks, Puffins and some 
Ducks are brightly colored or modified in form. 
Uses of the Wing . — The student should observe the relation be- 
tween the shape of a bird’s wing and the character of its flight and the 
further relation between the manner of its flight and its general habits. 
Fig. 12. Recurved bill of Avocet. (Two-thirds natural size.) 
Fig. 13. Long, pointed wing and small foot of Tree Swallow, an 
aerial bird. (Natural size.) 
Compare, for example, the wing of a Turkey Vulture with that of a 
Quail or Partridge; one aerial, the other terrestrial in habit. Note the 
lengthened flight-feathers and broad expanse of the Vulture’s wing, 
its comparative slowness in getting under way, its ability to soar 
indefinitely, in short, to remain in the air with the least possible expendi- 
ture of effort; while the rounded wing of the Quail, although incapable 
of prolonged flight and requiring great exertion for effective use, can 
nevertheless be employed at highest speed so quickly that the bird 
is in full flight almost the moment 
it leaves the ground. Continue 
the comparison through your list 
of birds, noting not only the power 
but the rhythm of the wing-stroke, 
whether it be regular or varied, 
whether the flight be direct or 
undulating, etc. 
Fig. 14. Short, rounded wing and large 
foot of Little Black Rail, a terrestrial bird. 
(Natural size.) 
