PERCHING BIRDS. 169 
for, wishing to satisfy myself on several points of their 
economy, I took the opportunity of the nests being 
within easy reach to examine them. All the empty 
ones, with the exception of one, swarmed with fleas, and 
I have no doubt had been forsaken from that cause. 
This little swallow generally arrives from a week to a 
fortnight before either of the others ; in some instances I 
have known it make its first appearance in March, quite 
regardless of the bleak cold winds. It is not, with us 
at least, seen much in the neighbourhood of houses, but 
prefers to seek its food over the meadows, and especially 
over water ; the stream that flows through the outskirts 
of the village is always frequented, while I have rarely 
seen them in the street. 
The flight of the sand martin, though rapid, is much 
less powerful than that of either the swallow or the 
martin, and I rarely remember to have seen it at those 
great altitudes attained by the latter in fine weather ; it 
appears to prefer skimming just above the surface of 
either stream or meadow. 
It is a pretty sight to watch a sandbank where their 
nests are abundant at the time they have young ones. 
Both parents take their part in feeding them, and dur- 
ing the greater part of the day it is seldom that many 
seconds elapse without one or other of them arriving 
with a supply. They are notwithstanding very discur- 
sive, and I have seen them constantly hawking for 
flies between two and three miles from their nearest 
nests. 
The Swift (Cypselws apus), though found in all parts 
of England, is very variable in regard to the numbers 
frequenting any particular locality. In some I know, 
two or three pairs are the most I have seen, while in 
