252 NATURAL HISTORY 



soon become impatient of confinement, and sit all day 

 with their heads out at the orifice, where the dams, by 

 clinging to the nest, supply them with food from morn- 

 ing to night. For a time, the young are fed on the wing 

 by their parents; but the feat is done by so quick and 

 almost imperceptible a slight, 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, con- 

 gregate in great flocks, and are the birds that are seen 

 clustering and hovering on sunny mornings and even- 

 ings round towers and steeples, and on the roofs of 

 churches and houses. These congregatings usually be- 

 gin 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 all together ; 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 fort- 

 night. 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 mo- 

 tion. 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 



