NOTES TO LETTER XX.
1 At Brandon, in Norfolk, are great heaps of sawdust which have settled down into solid masses. In these the sand-martins have burrowed and nested, just as they do in sand-banks. My attention was first drawn to this singular breeding-place by a note in the Transactions of the Norfolk and Norwich Naturalist's Field Club.
2 The largest colony of sand-martins I have ever seen was in a large gravel-pit at Oswestry, far from any large pool or river, although as a general rule these birds like the neighbourhood of water as White says.
3 This insect is not the bed-flea, but another, distinct also from those which trouble the swallow and the swift.
4 I once, late one evening, took a sand-martin off its nest, and it lay in the palm of my hand, not attempting to fly away, but apparently arranging itself again for sleep, and almost too lazy to scramble back again into its hole.
LETTER XXI.
Dear Sir,—As the swift or black-martin is the largest of the British hirundines, so it is undoubtedly the latest comer. For I remember but one instance of its appearing before the last week in April; and in some of our late frosty, harsh springs, it has not been seen till the beginning of May. This species usually arrives in pairs.
The swift, like the sand-martin, is very defective in architecture, making no crust, or shell, for its nest; but forming it of dry grasses and feathers, very rudely and inartificially put together. With all my attention to these birds. I have never been able once to discover one in the act of collecting or carrying in materials; so that I have suspected (since their nests are exactly the same) that they sometimes usurp upon the house-sparrows, and expel them, as sparrows do the house and sand-martin; well remembering that I have seen them squabbling together at the entrance of their holes, and the sparrows up in arms, and much disconcerted at these intruders. And yet I am assured, by a nice observer in such matters, that they do collect feathers for their nests in Andalusia, and that he has shot them with such materials in their mouths.
