OF SEL BORNE. 139 
not leave us in the winter, but lay themfelves up like infers and 
bats, in a torpid ftate, and llumber away the more uncomfortable 
months till the return of the fun and fine weather awakens them. 
But then we muft not, I think, deny migration in general ; be- 
caufe migration certainly does fijbfift in fome places, as my brother 
in Andalufta has fully informed me. Of the motions of thefe birds 
he has ocular demonftration, for many weeks together, both fpring 
and fall : during which periods myriads of the fwallow kind traverfe 
the Straits from north to foudi, and from fouth to north, according 
to the feafon. And thefe vafl: migrations confift not only of hir undines 
but of bee-birds, hoopoes, oro pendolos, or golden thrujloes. Sec. &c. and 
alfo of many of our foft-bilkd fummer birds of poJ[age ; and moreover 
of birds which never leave us, fuch as all the various forts of hawks 
and kites. Old Belon, two hundred years ago, gives a curious 
account of the incredible armies of hawks and kites which he favv 
in the fpring-time traverfing the I'hracian Bofphorus from Afia to 
Europe. Befides the above mentioned, he remarks that the procef- 
fion is fwelled by whole troops of eagles and vultures. 
Now it is no wonder that birds refiding in Africa fliould retreat 
before the fun as it advances, and retire to milder regions, and 
efpecially birds of prey, whofe blood being heated with hot animal 
food, are more impatient of a fultry climate : but then I cannot 
help wondering why kites and hawks, and fuch hardy birds as arc 
known to defy all the feverity of England, and even of Sweden and all 
north Europe, fhould want to migrate from the fouth oi Europe, and 
be diffatisfied with the winters o( Andahfia. 
It does not appear to me that much ftrefs may be laid on the 
difficulty and hazard that birds muft run in their migrations, by rea- 
fon of vaft oceans, crofs winds, &c.; becaufc, if we refied:, a bird 
may travel fi-om England to the equator without launching out and 
T 2, expofing 
