f the house-
martins do not depart in the winter far from this village. I therefore
determined to make some search about the south-east end of the hill,
where I imagined they might slumber out the uncomfortable months of
winter. But supposing that the examination would be made to the best
advantage in the spring, and observing that no martins had appeared by
the 11th April last; on that day I employed some men to explore the
shrubs and cavities of the suspected spot. The persons took pains, but
without any success; however, a remarkable incident occurred in the midst
of our pursuit: while the labourers were at work, a house-martin, the
first that had been seen this year, came down the village in the sight of
several people, and went at once into a nest, where it stayed a short
time, and then flew over the houses; for some days after no martins were
observed, not till the 16th April, and then only a pair. Martins in
general were remarkably late this year.

LETTER LII.

SELBORNE, _Sept._ 9_th_, 1781.

I have just met with a circumstance respecting swifts, which furnishes an
exception to the whole tenor of my observations ever since I have
bestowed any attention on that species of hirundines. Our swifts, in
general, withdrew this year about the first day of August, all save one
pair, which in two or three days was reduced to a single bird. The
perseverance of this individual made me suspect that the strongest of
motives, that of an attachment to her young, could alone occasion so late
a stay. I watched therefore till the 24th August, and then discovered
that, under the eaves of the church, she attended upon two young, which
were fledged, and now put out their white chins from a crevice. These
remained till the 27th, looking more alert every day, and seeming to long
to be on the wing. After this day they were missing at once; nor could I
ever observe them with their dam coursing round the church in the act of
learning to fly, as the first broods evidently do. On the 31st I caused
the eaves to be searched, but we found in the nest only two callow dead,
stinking swifts, on which a second nest had been formed. This double
nest was full of the black shining cases of the _hippoboscae hirundinis_.

The following remarks on this unusual incident are obvious. The first
is, that though it may be disagreeable to swifts to remain beyond the
beginning of August, yet that they can subsist longer is undeniable. The