120 
[LETT. 
LETTER XLIL 
TO THE HONOURABLE DA IKES BARRING TON. 
You are, I know, no great friend to migration ; and the well- 
. attested accounts from various parts of the kingdom seem to 
justify you in your suspicions, that at least many of the swallow 
kind do not leave us in the winter, hut lay themselves up like 
insects and hats, in a torpid state, and sluniher away the more 
unconifortahle months till the return of the sun and fine weather 
awakens them. 
But then we must not, I think, deny migration in general ; 
because migration certainly does subsist in some places, as my 
brother in Andalusia has fully informed me. Of the motions 
of these birds he has ocular demonstration, for many weeks 
together, both spring and fall: during which periods myriads of 
the swallow kind traverse the Straits from north to south, and 
from south to north, according to the season ; and these vast 
migrations consist not only of liirunclincs, but of bee-birds, 
hoopoes, Oro jjcndolos, or golden thrushes, &c. &c., and also of 
many of our soft-billed summer birds of passage; and moreover 
of birds which never leave us, such as all the various sorts 
of hawks and kites. Old Belon, two hundred years ago, gives 
a curious account of the incredible armies of hawks and kites 
which he saw in the spring-time traversing the Thracian Bos- 
porus from Asia to Europe. Besides the above-mentioned, 
he remarks that the procession is swelled by whole troops of 
eagles and vultures. 
Nov/ it is no wonder that birds residing in Africa, and 
especially birds of prey whose blood being heated with hot 
animal food are more impatient of a sultry climate, should 
retreat before the sun as it advances, and retire to milder 
regions ; but then I cannot help wondering why kites and 
hawks, and such hardy birds as are known to defy all the 
severity of England, and even of Sweden and all north Europe, 
