154 NATURAL HISTORY 



thrusting their tails out at the aperture of their nest. As the 

 young of small birds presently arrive at their rjXi/cia, or full 

 growth, they 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 morning 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 imper- 

 ceptible 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, 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 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 fortnight. These industrious ar- 

 tificers 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 an hot stifled 

 inn-yard, against a wall facing to the south. 



