THE PERCHING BIRDS. 167 



the marvellous turns, be a wonderfully efficient steering 

 gear. The swallow commences building its remarkable 

 nest under the eaves of houses on arrival. Mud, its prin- 

 cipal ingredient, is incorporated with hair and grass, and 

 the familiar nest is lined with soft grasses or feathers, 

 and has a single opening above. When black clay is used, 

 such a nest will last for years. The bird has also, though 

 rarely, been known to nest in trees and on the sea-cliffs ; 

 and it has been shown, by the simple expedient of mark- 

 ing them, that these birds will return year after year to 

 the same nest. Eggs, 5 or 6, i inch ; white, speckled and 

 spotted with brown. A second — some say even a third — 

 brood is reared. 



The Martin is another of the birds spared by schoolboys, 

 not wholly, let us hope, because its rapid flight renders it 



^ . particularly difficult to shoot. It arrives soon 



after the first swallows, leaving again early in 

 October, and is a sociable bird. Its food consists entirely 

 of insects, which it chases, with flight somewhat inferior 

 to that of the swallow, high and low. The notion that 

 these birds act as barometers, forecasting fine weather 

 when they hawk at a height, and vice versa, is no fanciful 

 one, the explanation being that their insect prey flies close 

 to the ground Avhen the glass is low. In Euro^^e this bird 

 is little persecuted by man, but Michelet gives an instance 

 in which its virtual extermination in the Isle de Bourbon 

 brought down on the farmers a plague of grasshoppers 

 that went near to ruin them. I do not, of course, vouch 

 for the truth of his statement. 



The martin nests in the eaves of houses and in steeples, 

 its nest differing from that of the swallow in its rougher 

 surface and in the position of the opening, which is here 

 at the side. The bird itself is distinguished from the 

 swallow by the slighter forking of the tail, the white 

 throat, and the white feathers on the legs and feet. Eggs, 

 5, I inch ; pure white. Like the swallow, this bird rears 



