Ruby-throated Hummingbird 183 
tunate the house where a colony elect to live, 
for they rid the air of myriads of gnats and 
mosquitoes, as they fly about overhead, sil- 
houetted against the sky. Early in the morning 
and late in the afternoon are their hours for 
exercise. You will think, perhaps, that they 
look more like bats than birds. Watch their 
rapid wing-beats very closely and see if you can 
settle the mooted question as to whether they 
use both wings at once, or first one wing and 
then the other in alternate strokes. After you 
have noticed their peculiar, throbbing flight, 
you will never again confuse them with the 
graceful, gliding swallows. Although the swift 
is actually shorter than a sparrow, its spread 
wings measure over a foot across from tip to 
tip. No wonder it can fly every waking mo- 
ment without feeling tired, and journey from 
Labrador to Central America for a winter 
holiday. 
RUBY-THROATED HUMMINGBIRD 
What child does not know the hummingbird, 
the jewelled midget that flashes through the 
garden, poises before a flower as if suspended 
in the air by magic, thrusts a needle-like bill into 
one cup of nectar after another, then whirs 
off out of sight in a trice? It is the smallest 
