NATURAL HISTORY OF SELBORNE. 159 
day with their heads out at the orifice, where the dams, by clinging 
to the nest, supply them with food from morning to night. Fora 
time the young are fed on the wing by their parents ; but the feat 
is done by so quick and almost imperceptible a flight that a person 
must have attended very exactly to their motions before he would 
be able to perceive it. As soon as the young are able to shift for 
themselves, the dams immediately turn their thoughts to the 
business of a second brood; while the first flight, shaken off and 
rejected by their nurses, congregate in great flocks, and are the 
birds that are seen clustering and hovering on sunny mornings and 
evenings round towers and steeples, and on the roofs of churches 
and houses. These congregatings usually begin to take place 
about the first week in August; and therefore we may conclude 
that by that time the first flight is pretty well over. The young 
of this species do not quit their abodes altogether ; but the more 
forward birds get abroad some days before the rest. These 
approaching the eaves of buildings, and playing about before them, 
make people think that several old ones. attend one nest. They 
are often capricious in fixing on a nesting-place, beginning many 
edifices, and leaving them unfinished; but when once a nest is 
completed in a sheltered place, it serves for several seasons, 
Those which breed in a ready-finished house get the start in 
hatching of those that build new by ten days or a fortnight. 
These industrious artificers are at their labours in the long days 
before four in the morning. When they fix their materials they 
plaster them on with their chins, moving their heads with a quick 
vibratory motion. They dip and wash as they fly sometimes in 
very hot weather, but not so frequently as swallows. It has been 
observed that martins usually build to a north-east or north-west 
aspect, that the heat of the sun may not crack and destroy their 
nests; but instances are also remembered where they bred for 
many years in vast abundance in a hot stifled inn-yard against a 
wall facing to the south. 
Birds in general are wise in their choice of situation ; but in this 
neighbourhood every summer is seen a strong proof to the contrary 
at an house without eaves in an exposed district, where some 
martins build year by year in the corners of the windows, But, as 
the corners of these windows (which face to the south-east and 
south-west) are too shallow, the nests are washed down every hard 
rain ; and yet these birds drudge on to no purpose from summer to 
summer, without changing their aspect or house. It is a piteous 
