84 THE NATURAL HISTORY OF SELBORNE. 
in infinite numbers, occasioning such a rushing from the 
strokes of their wings against the hazy air, as might be heard 
to a considerable distance: since that no flock has appeared, 
only a few stragglers. 
Some swifts stayed late, till the 22d of August—a rare 
instance! for they usually withdraw within the first week.* 
On September 24th three or four ring-ousels appeared in my 
fields for the first time this season; how punctual are these 
visitors in their autumnal and spring migrations ! 
LETTER XXXVIII. 
SELBORNE, March 15th, 1773. 
By my journal for last autumn it appears that the house- 
martins bred very late, and stayed very late in these parts ; 
for, on the rst of October, I saw young martins in their nest 
nearly fledged; and again on the 21st of October, we had at 
the next house a nest full of young martins just ready to fly, 
and the old ones were hawking for insects with great alertness. 
The next morning the brood forsook their nest, and were flying 
round the village. From this day I never saw one of the 
swallow kind till November 3d, when twenty, or perhaps 
thirty, house-martins were playing all day long by the side of 
the hanging wood, and over my field. Did these small weak 
birds, some of which were nestling twelve days ago, shift their 
quarters at this late season of the year to the other side of the 
northern tropic? Or rather, is it not more probable that the 
next church, ruin, chalk-cliff, steep covert, or perhaps sand- 
bank, lake or pool (as a more northern naturalist would say), 
may become their hybernaculum, and afford them a ready and 
obvious retreat ? 
1 See Letter LII, to Mr. Barrington. 
