134 HABITS OF BIRDS. 
effort to fly away. All the swallows of the large 
basin between the bridges of the Tuileries and the 
Pont Neuf, and perhaps from places more remote, 
had assembled to the number of several thousands. 
Their flight was like a cloud; all uttered a cry of 
pity and alarm. After some hesitation and a tu- 
multuous counsel, one of them fell upon a device 
for delivering their companion, communicated it to 
the rest, and began to put it into execution. Each 
took his place; all those who were at hand went in 
turn, as in the sport of running at the ring, and, in 
passing, struck the thread with their bills. ‘These 
efforts, directed to one point, were continued every 
second, and even more frequently. Half an hour 
was passed in this kind of labour before the thread 
was severed and the captive restored to liberty. 
But the flock, only a little diminished,” adds M. 
Dupont de Nemours, “remained until night, chat- 
tering continually in a tone which no longer be- 
trayed anxiety, and as if making mutual felicita- 
tions and recitals of their achievement.” 
Now we doubt not that these swallows crowded 
’ to their companion, as M. Dupont has recorded, for 
all small birds are apt to come when called by their 
fellows, as is well known to birdcatchers, who 
employ callbirds to bring the wild ones to their 
nets; but we much doubt whether they united their 
efforts with the design of cutting the string, and 
think the observer must have been deceived as to 
this particular. In a similar instance of a pair of 
sparrows becoming entangled, which fell under our 
observation, their neighbours crowded to the place, 
but, apparently, only for the purpose of scolding, 
not of assisting the entangled birds. ; 
It is rare indeed among quadrupeds, and rarer 
still, if it occur at all, among birds, to meet with 
instances of mutual assistance, such as we find so 
strikingly exemplified among social insects. Bea- 
vers unite in forming dams across a stream and in 
