ROOK. H5 
chiefly attribute the equal dispersion of birds m the spring over 
tne face of the country. 
Now as to the business of food : as these animals are actuated 
by instinct to hunt for necessary food, they should not, one 
would suppose, crowd together in pursuit of sustenance at a 
time when it is most likely to fail ; yet such associations do take 
place in hard weather chiefly, and thicken as the severity in- 
creases. As some kind of self-interest and self-defence is no 
doubt the motive for the proceeding, may it not arise from the 
helplessness of their state in such rigorous seasons : as men 
crowd together, v^^hen under great calamities, though they know 
not why? Perhaps approximation may dispel some degree of 
cold ; and a crowd may make each individual appear safer from 
the ravages of birds of prey and other dangers. 
If I admire when I see how much congenerous birds love to 
congregate, I am the more struck when I see incongruous ones 
in such strict amity. If we do not 
much wonder to see a flock of rooks 
usually attended by a train of daws, 
yet it is strange that the former should 
so frequently have a flight of starlings 
for their satellites. Is it because rooks 
have a more discerning scent than 
their attendants, and can lead them to Rook, 
spots more productive of food ? Anatomists say that rooks, by 
reason of two large nerves which run down between the eyes into 
the upper mandible, have a more dehcate- feehng in their beaks 
than other round-billed birds, and can grope for their meat when 
out of sight. Perhaps then their associates attend them on the 
motive of interest, as greyhounds wait on the motions of their 
finders ; and as lions are said to do on the yelpings of jackals 
Lapwings and starUngs sometimes associate. 
LETTER XII. To the Hon. DAINES BARRINGTON. 
DEAR SIR, Selborne, March 9, 1772. 
As a gentleman and myself were walking on the fourth of last 
November round the sea-banks at Newhaven, near the mouth of 
the Lewes river, in pursuit of natural knowledge, we were sur- 
prised to see three house-swallows gliding very swiftly bv m. 
