BIRDS — GENERAL INTELLIGENCE. 
319 
A pair of swallows built their nest against one of the first- 
floor windows of an uninhabited house in Merrion Square, 
Dublin. A sparrow, however, took possession of it, and the 
swallows were repeatedly seen clinging to the nest, and en- 
deavouring to gain an entrance to the abode they had erected 
with so much labour. All their efforts, however, were defeated 
by the sparrow, who never once quitted the nest. The perse- 
verance of the swallows was at length exhausted : they took 
flight, but shortly afterwards returned, accompanied by a 
number of their congeners, each of them having a piece of dirt 
in its bill. By this means they succeeded in stopping up the 
hole, and the intruder was immured in total darkness. Soon 
afterwards the nest was taken down and exhibited to several 
persons, with the dead sparrow in it. In this case there ap- 
pears to have been not only a reasoning faculty, but the birds 
must have been possessed of the power of communicating their 
resentment and their wishes to their friends, without whose aid 
they could not thus have avenged the injury they had sus- 
tained. 1 
That birds sometimes act in concert may also be 
gathered from the following observations recorded by Mr. 
Buck :■ — - 
I have constantly seen a flock of pelicans, when on the feed, 
form a line across a lake, and drive the fish before them up its 
whole length, just as fishermen would with a net . 2 
The following is extracted from Sir E. Tennent’s 
‘ Natural History of Ceylon, 5 and displays remarkable in- 
telligence on the part of the crows in that island — 
One of these ingenious marauders, after vainly attitudi- 
nising in front of a chained watch-dog, that was lazily gnawing 
a bone, and after fruitlessly endeavouring to divert his attention 
by dancing before him, with head awry and eye askance, at 
length flew away for a moment, and returned bringing a com- 
panion which perched itself on a branch a few yards in the 
rear. The crow’s grimaces were now actively renewed, but 
with no better success, till its confederate, poising itself 
on its wings, descended with the utmost velocity, striking the 
dog upon the spine with all the force of its strong beak. The 
ruse was successful ; the dog started with surprise and pain, 
but not quickly enough to seize his assailant, whilst the bone he 
had been gnawing was snatched away by the first crow the 
1 Ibid , p. 99. * Nature , vol. xiii., p. 303. 
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