BAKE SWALLOW OR SAND MARTIN. 
191 
their summer residence, great numbers die in their holes, and many have 
been found there in a state bordering on torpidity. 
Their food, which consists of small insects, principally of the hymenop- 
terous kind, even during winter in the Floridas, is procured on wing. 
They very seldom approach walls or the trunks of trees to seize them, but 
frequently snatch them from the tops of grasses or other plants on which 
they have alighted. They also seize small aquatic insects ; but, although 
I suspect that they disgorge in pellets the harder parts of these, I have no 
proof, obtained from actual observation, that they do so. 
The holes perforated by this species for the purpose of breeding require 
considerable exertion and labour. They are usually boi'ed at the distance 
of two or three feet from the summit of the bank or surface of the ground, 
to the depth of about three feet, but sometimes to that of four or even five. 
They are near each other or remote, according to the number of pairs of 
Swallows that 'resort to that place, and the extent of the bank. In one 
situation you may find not more than a dozen pairs at work, while in 
another several hundreds of holes may be seen scattered over some hun- 
dreds of yards. On the bluffs of the Ohio and the Mississippi there are 
many very extensive breeding-places. While engaged in digging a sand- 
bank on the shores of the Ohio, at Henderson, for the purpose of erecting 
a steam-mill, I was both amused and vexed by the pertinacity with which 
the little winged labourers continued to bore holes day after day, whilst 
the pickaxes and shovels demolished them in succession. The birds seemed 
to have formed a strong attachment to the place, perhaps on account of 
the fine texture of the soil, as I observed many who had begun holes a few 
hundred yards off abandon them, and join those engaged in the newly 
opened excavation. Whether the holes are frequently bored horizontally 
or not I cannot say, but many which I examined differed in this respect 
from those described by authors, for on introducing a gun-rod or other 
■straight stick, I found them to have an inclination of about ten degrees up- 
wards. The end of the hole is enlarged in the form of an oven, for the recep- 
tion of the nest, and the accommodation of the parents and their brood. 
When the birds have for awhile examined the nature of the bank, they 
begin their work by alighting against it, securing themselves by the claws, 
and spreading their tails considerably, so as, by being pressed against the 
surface, to support the body. The bill is now employed in picking the soil, 
until a space large enough to admit the body of the bird is formed, when the 
feet and claws are also used in scratching out the sand. I have thought that 
the slight ascent of the burrow contributed considerably to enable the bird 
to perforin the severe task of disposing of the loose materials, which are seen 
dropping out at irregular intervals. Both sexes work alternately, in the 
