140 SWALLOW. 
notwithstanding that the Swallows kept up a good resistance, 
and even brought others to assist them. ‘The intruders were 
left in peaceable possession of the nest, till the two old birds 
were obliged to quit it to provide food for their young. They 
had no sooner departed, than several Swallows came and broke 
down the nest, and I saw the young Sparrows lying dead on 
the ground. As soon as the nest was demolished, the Swallows 
began to rebuild it.’ 
Every one must have observed that on a sudden ‘note of 
exclamation,’ given by a single Swallow, the whole flock, which 
may have been previously congregated on some spot near, on 
a sudden dash off in a strange and unaccountable manner. 
‘A Swallow, apparently at some height in the air, utters two 
shrill notes; on hearing which the whole of the flock quit 
the water, and rise into the air, so as almost to disappear 
from the sight. After a short time they return to hawk for 
flies, and touch the surface of the river at exactly the same 
place they had just before quitted.’ ‘On mentioning this 
circumstance to an observant friend, he informed me that 
when he was lately at Malvern, he had observed the effect of 
the two notes I have just described. A large number of 
Swallows had congregated on the roof of a house at that place. 
The preceding evening had been cold and somewhat frostiy, so 
that early in the morning the Swallows were so torpid that 
he caught two or three of them in his hand, as they rested 
on the roof near the window of the room in which he slept. 
While they were in this state, he heard two shrill notes from 
a Swallow, and in an instant the whole of them took wing 
simultaneously, and having made two or three circuits in the 
air, disappeared altogether. He fancied that these circuits were 
preparatory to their migration, but they were more probably 
a notice that food was at hand. At all events it seems clear 
to me, that there is a master or leading Swallow who guides 
the movements of the rest.’ 
Swallows may often be seen pursuing birds of prey, and on 
returning from a chase of this kind, ‘unite in a song, 
(apparently,) of exultation.’ Mr. Thompson, of Belfast, records 
two curious instances, one of them witnessed by himself, of 
their flying up and down to and from the top of a very tall 
chimney. “There was a constant stream of birds ascending 
and descending; their flight had a most singular appearance, 
from the circumstance of their flying upwards from the ground 
to the chimney top almost in a vertical line, and coming down 
