ches, etc? Before winter perhaps they
might be hardened, and able to shift for themselves.

About ten years ago I used to spend some weeks yearly at Sunbury, which
is one of those pleasant villages lying on the Thames, near Hampton
Court. In the autumn, I could not help being much amused with those
myriads of the swallow kind which assemble in those parts. But what
struck me most was, that, from the time they began to congregate,
forsaking the chimneys and houses, they roosted every night in the
osier-beds of the aits of that river. Now, this resorting towards that
element, at that season of the year, seems to give some countenance to
the northern opinion (strange as it is) of their retiring under water. A
Swedish naturalist is so much persuaded of that fact, that he talks, in
his calendar of Flora, as familiarly of the swallows going under water in
the beginning of September, as he would of his poultry going to roost a
little before sunset.

An observing gentleman in London writes me word that he saw a
house-martin, on the twenty-third of last October, flying in and out of
its nest in the Borough. And I myself, on the twenty-ninth of last
October (as I was travelling through Oxford), saw four or five swallows
hovering round and settling on the roof of the county hospital.

Now is it likely that these poor little birds (which perhaps had not been
hatched but a few weeks) should, at that late season of the year, and
from so midland a county, attempt a voyage to Goree or Senegal, almost as
far as the equator?

I acquiesce entirely in your opinion--that, though most of the swallow
kind may migrate, yet that some do stay behind and hide with us during
the winter.

As to the short-winged, soft-billed birds, which come trooping in such
numbers in the spring, I am at a loss even what to suspect about them. I
watched them narrowly this year, and saw them abound till about
Michaelmas, when they appeared no longer. Subsist they cannot openly
among us, and yet elude the eyes of the inquisitive; and, as to their
hiding, no man pretends to have found any of them in a torpid state in
the winter. But with regard to their migration, what difficulties attend
that supposition! that such feeble bad fliers (who the summer long never
flit but from hedge to hedge) should be able to traverse vast seas and
continents in order to enjoy milder seasons amidst the regions of Africa!

LETTER XIII.