190 
BANK SWALLOW OR SAND MARTIN. 
hundreds of pairs about their breeding places, passing, repassing, and cross- 
ing each other in various ways, you almost wonder that they never come 
into collision with each other. The slightest movement in any direction 
seems sufficient to enable them to overtake and secure their prey ; and 
they less frequently than any other species follow an insect upward to any 
great distance. Like all other Swallows, they drink and bathe on wing. 
Their migrations are performed by day, although perhaps continued by 
night, and their movements are more desultory and rather slower than 
those of other Swallows. It is rare to observe them in great flocks at that 
time, their associations not being apparently formed until they reach the 
countries in which they spend the winter months. Their flight, when they 
are thus travelling, is continued rather low over the land or the water ; 
and as in America they retire to a less distance southward than our other 
Swallows, they are not unfrequently seen to linger behind the rest. In 
South Carolina, indeed, I have seen some in November. 
In summer and autumn they roost in the holes excavated for their nests ; 
but in winter, at least in the Floridas., they always repose at night among 
the tall grass of the salt marshes, making choice of situations sheltered by 
the winds and not liable to be overflowed. At this time they keep together 
in large bodies while searching for food. I have several times accidentally 
crossed their roosting places, which I at once recognised by the quantity 
of their dung attached to the blades, and lying on the ground, and from 
which I infer that they rest clinging to the plants. 
At the first appearance of spring they leave their winter quarters in 
pairs, or singly, or in very small flocks ; but they follow each other so 
closely in this manner as to form an almost continued line of march. I 
had the pleasure of observing this to be the case with the Barn Swallow 
also, whilst I was proceeding toward the Texas, when that species was 
advancing in a contrary direction. 
Although small, the Sand Swallow is a rather hardy bird ; for I observed 
that the transient cold weather that at times occurs in the Floridas at night, 
seldom forces them to remove farther south. On one occasion, however, 
when the ice was about the thickness of a dollar, many were found dead 
along the shores, as well as floating on the water, whilst the rest appeared in 
great perturbation, wending their way in a hurried manner toward the 
warmer parts of the country, and taking advantage of- every spot. that afford- 
ed them more warmth, such as the borders of woods, and high banks of 
streams. I am, however, of opinion that the inclemency of the weather at 
times proves to be the greatest evil these birds have to encounter, especially 
when in early spring they arermoving northward, and occasionally meet 
with a sudden change from temperate to cold. Even in the places selected for 
