164 HANDBOOK OF BRITISH INLAND BIRDS 
arrival, and it usually vanishes about the tenth of 
August. Its nearest British relative is the Night- 
jar, and this bird arrives even later ; on the other 
hand, it does not leave us till September. We do 
not yet know enough to explain with certainty the 
reason of those smaller differences in habit, but it 
is clear that, broadly speaking, both these insect- 
eating birds can only subsist in this climate at the 
time when the supply of insect life is at its highest 
summer level. The plumage of the Swift is a 
dull, sooty black all over, except for a small 
greyish patch under the chin. The immense 
length of the scythe-shaped wings, and the short- 
ness and feebleness of the legs and feet, make it as 
helpless upon the ground as it is perfectly at home 
in the air, and it has very great difficulty in rising 
again, if by some mishap, such as striking a tele- 
graph wire, it finds itself stranded on terra firma. 
From the mouth of its nesting-holes it takes wing 
with a downward plunge. It breeds in holes and 
crevices under the roof of buildings, from castle 
towers to low thatched cottages, and in other holes 
in masonry, or the sides of a cliff or quarry. The 
nest is a small, flat heap of straws, feathers, and 
dusty rubbish, partly glued together by the 
glutinous moisture of the bird's mouth. Such of 
the nesting material as the Swift does not find in 
the selected hole it snaps up upon the wing. Two 
