CHIMNEY SWIFTS 
Over large areas of the United States, farm house chimneys are occupied 
each summer by one or more families of chimney swifts. Previously these 
diminutive gray birds made their homes in hollow trees, but today civiliza¬ 
tion has provided them with more comfortable homes. They make a nest of 
twigs, which they cement to the brick or stone with their saliva. These twigs 
are torn off dead trees by the birds when in full flight. 
The nest of the chimney swift, rather resembling a basket, takes some 
eighteen days to build. Wet weather interferes with construction, dissolving 
the saliva-cement. The mother bird lays one brood each year, consisting of 
four or five (rarely six) eggs. The incubation period lasts eighteen to twenty- 
two days, male and female relieving one another in sitting on the eggs. The 
glands providing the glue for nest building are much swollen at nesting 
time; when the swelling goes down, cheek pouches are formed in which 
quantities of small insects can be packed. 
These birds are beneficial to farmers as they eat caterpillars and other 
insect pests. When prolonged rain clears the air of insects and drives the 
caterpillars to shelter, the swifts are apt to be doomed to starvation. In 
June, 1903, this occurred, and dead swifts were removed from the chim¬ 
neys of New England by the bushel. 
Chimney swifts are friendly, sociable birds. Their flight is exceed¬ 
ingly rapid, and rarely can they be overtaken, even by the swiftest falcons. 
They fly in zig-zags and curves, twittering shrilly, apparently never resting 
on trees or on the ground. Utterly fearless, they fly through tempests and 
thunderstorms. They drink and bathe in streams when on the wing, and 
occasionally one of them dips in too deep and is unable to rise again. They 
sleep clinging to a vertical surface such as the inside of their chimney home. 
On their migrations chimney swifts often spend their nights in dead 
trees. One tree is related to have held eight thousand or nine thousand of 
them at a time. When the birds entered or left the tree, the noise was said 
to be like “the sound of a large wheel revolving under a powerful stream.” 
It required more than half an hour for all the birds to leave. 
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