THE LANGUAGE OF BIRDS. 143 
his great length of wing, he is likewise provided with 
a long forked tail, which acts as a rudder, enabling 
him to turn with the greatest rapidity. It is affirmed 
that the swallow tribe do not come hither for warm 
weather, nor retire from cold, but because in the 
summer our air is fuller of fogs and damps than 
other countries, and for that reason breeds a more 
numerous variety of insects ; and it has happened, 
when the air has been dry and hot, the insects have 
died, — in consequence of which, the swallows have 
perished from want, falling down dead out of the 
air : the like results occur in cold weather. Thus 
instinct teaches them to follow their food. 
The house or chimney swallow builds a nest with 
great art and industry, composed of clay, strength- 
ened with straw and horse-hair, and lined with 
feathers. In this nest the hen lays five or six eggs, 
and sometimes rears a second brood in the year. This 
occurs when the parents come early, and the season 
proves particularly mild, and they pair soon; but 
should the weather prove severe, or their nests be 
robbed in the beginning of the season, this important 
task is frequently deferred to September, when they 
find a difficulty in rearing even one nest. 
