OF NEW ENGLAND. 149 
time as the Cliff Swallows, but I have never observed them in 
company with those birds. They may be seen in their sum- 
mer-haunts flying either over the surface of land and water, or 
at some height in the air, though rarely very far above the 
ground. They fly much like the other swallows, though per- 
haps less steadily and with less sailing, but they seldom wan- 
der far from the banks in which their nests are placed. They 
are found throughout New England, and much further to the 
northward, but are much confined to localities, both because 
of their disposition to colonize, and the necessity of their se- 
lecting a place where the earth is of a character suitable to 
their purposes. 
Their choice of a summer-home is undoubtedly influenced 
very considerably by the nature of the soil, as it is impossible 
for them to burrow in all kinds of earth. Extremely inter- 
esting details may be learned through the study of their exca- 
vations, as these latter vary greatly in size, depth, and the 
angle at which they run, in accordance with the variation of 
the soil. The Bank Swallows invariably select a bank, the 
sand of which will not ‘‘cave in,” and then burrow to a 
stratum where the pebbles, which might fall down upon their 
egos or young, are not found. Their colonies sometimes in- 
crease from year to year with rapidity, and, if not disturbed, 
in the course of a few seasons consist of a large number of 
excavations. 
How wonderful is that instinct which enables these swallows 
to find out the best places for their homes, and how wonderful 
their skill in making these secure! When a small party boldly 
advance to a country, hitherto unknown to them, who can de- 
fine that sense which enables them to discover and select the 
most fitting bank for their purposes, or even the best part of 
it? What, indeed, prompts them to part from their fellows 
and to become pioneers in new settlements? Instinct can 
never be fully understood by man, nor its workings. 
Wilson, speaking of the ‘‘Sand Martins,” says :—‘‘ We have 
sometimes several days of cold rain and severe weather af- 
ter their arrival in spring, from which they take refuge in 
1 
