NATURAL HISTORY OF SELBORNE. 
129 
The following circumstance should by no means be omitted — that 
these birds do not make use of their caverns by way of hybernacula, as 
might be expected ; since banks so perforated have been dug out with 
care in the winter, when nothing was found but empty nests. 
The sand-martin arrives much about the same time with the 
swallow, and lays, as she does, from four to six white eggs. But as 
this species is cryptogame, carrying on the business of nidification, 
incubation, and the support of its young in the dark, it would not be 
so easy to ascertain the time of breeding, were it not for the coming 
forth of the broods, which appear much about the time, or rather 
somewhat earlier than those of the swallow. The nestlings are supported 
in common like those of their congeners, with gnats and other small 
insects ; and sometimes they are fed with lihellulm (dragon-flies) almost 
as long as themselves. In the last week in June we have seen a row of 
these sitting on a rail near a great pool as perchers, and so young and 
helpless, as easily to be taken by hand ; but whether the dams ever 
feed thena on the wing, as swallows and house-martins do, we have 
never yet been able to determine ; nor do we know whether they 
pursue and attack birds of prey. 
When they happen to breed near hedges and enclosures, they are 
dispossessed of their breeding holes by the house-sparrow, which is on 
the same account a fell adversary to house-martins. 
These hirundines are no songsters, but rather mute, making only a 
little harsh noise when a person approaches their nests. They seem not 
to be of a sociable turn, never with us congregating with their congeners 
in the autumn. Undoubtedly they breed a second time, like the house- 
martin and swallow ; and withdraw about Michaelmas. 
Though in some particular districts they may happen to abound, 
yet in the whole, in the south of England at least, is this much the 
rarest species. For there are few towns or large villages but what 
abound with house-martins ; few churches, towers, or steeples, but what 
are haunted by some swifts ; scarce a hamlet or single cottage-chimney 
that has not its swallow ; while the bank-martins, scattered here and 
there, live a sequestered life among some abrupt sand-hills, and in the 
banks of some few rivers. 
These birds have a peculiar manner of flying ; flitting about with 
odd jerks, and vacillations, not unlike the motions of a butterfly. 
Doubtless the flight of all hirundines is influenced by, and adapted to, 
the peculiar sort of insects which furnish their food. Hence it would 
be worth inquiry to examine what particular genus of insects aflfords 
the principal food of each respective species of swallow. 
Notwithstanding what has been advanced above, some few sand- 
martins, I see, haunt the skirts of London, frequenting the dirty pools 
in Saint George's Fields, and about Whitechapel. The question is 
where these build, since there are no banks or bold shores in that 
neighbourhood ; perhaps they nestle in the scaffold holes of some old 
or new deserted building. They dip and wash as they fly sometimes, 
like the house-martin and swallow. 
Sand-martins diff*er from their congeners in the diminutiveness of 
their size, and in their colour, which is what is usually called a mouse- 
