i8o Birds Every Child Should Know 
the insects on them, just as cowbirds follow 
our cattle; and he imagined the bird was 
actually drinking the goat’s milk! 
CHIMNEY SWIFT 
There are some children, and grown-ups, too, 
who persist in calling this bird the chimney 
swallow, although it is not even remotely 
related to the swallow family, and its life his- 
tory, as well as its anatomy, are quite different 
from a swallow’s, as you shall see. 
Down within some unused chimney, the 
modern babies of this soot-coloured, dark, 
grayish-brown bird first open their eyes. Old- 
fashioned swifts still nest in hollow trees or 
caves, but chimneys are so much more abundant 
and convenient, that up-to-date birds prefer 
them. Without stopping in their flight, the 
parent swifts snap off with their beaks or feet, 
little twigs at the ends of dead branches, and 
these they carry, one by one, into a chimney, 
gluing them against the side until they have 
finished an almost flat, shelf -like, lattice cradle. 
Where do they get their glue? Only during 
the nesting season do certain glands in their 
mouths flow a brownish fluid that quickly gums 
and hardens when exposed to the air. After 
nursery duties have ended, the gland shrinks 
