142 " THE FEATHERED TRIBES. 



bird of large salivary glands adds still further corroboration. Pennant mentions that 

 the martins sometimes build in cliffs ovcrhauo;ino- the sea, and in the romantic and 

 beautiful dell of Hawford, in Ayrshire, some may be found among the wooded rocks, at 

 the base of which winds the river Ayr. 



The martin lays four or five eggs, after an incubation of thirteen days. This bird is 

 inferior in size to the common swallow. The whole of the upper parts are characterised 

 by their beautifully blue-black glossy appearance, while the under parts are white. The 

 legs are covered with a white down, and the claws are white. The tail is blue-black, 

 and forked. 



THE SAND-MARTIN.* 



The sand-martin, or, as it is termed by the Spaniards, the mountain butterfly, is 

 another sjDecies of swallow. It selects as the spot where its nest shall be made the high 

 banks of rivers, railway cuttings, and other vertical surfaces of earth which are not of 

 material too hard to resist its efforts. It avoids rocky and clay districts, because the 

 material would be unsuitable to their operations. Having determined on a suitable 

 situation, which is generally such as lias been employed by others of its race in past 

 years, the little miner forms a horizontal orifice, with a degree of regularity and an 

 amount of labour which is rarely exceeded among birds. The beak of the sand-martin 

 is very hard, sharp, and admirably adapted for digging, and though small, its shortness 

 increases its strength. Clinging to the face of a sand-bank, it strikes with its bill as a 

 miner would with a pickaxe, till it has loosened a considerable portion of the hard sand, 

 which it tumbles down the fiice of the cliff. Some of these holes are cut with such pre- 

 cision as to appear to have been marked out with a pair of compasses, while dthers are 

 irregular in form ; but this seems rather to arise from the crumbling away of the sand 

 than from any deficiency in skill. The bird alwaj^s uses his own body to determine the 

 proportions of the gallerj' ; it perches on the circumference with its claws, and works 

 with its biU from the centre outwards. It consequently assumes all positions while at 

 work at the inside, hanging from the roof of the gallery with its back downwards as 

 often as standing on the floor ; and sometimes it has been seen wheeling round in this 

 manner on the face of a sand-banls:, when it was just breaking ground, to begin its 

 gallery. To this it is owing that all the galleries arc more or less tortuous in their ter- 

 mination ; and there a bed of loose hay, and a few of the smaller breast feathers of geese, 

 ducks, or fowls, are spread with little art for the reception of the eggs. It is worthy of 

 remark that the bird always scrapes the loose sand with his feet which it has detached 

 by its bill ; but so carefully is this accomplished that it does not remove the uumined 

 sand, or disturb the true level of the floor. 



It lias been observed that there are holes sometimes unfinished by these birds, the 

 tunnelling being carried on for some distance, and then left uncompleted. This has led 

 to the supposition that it is an intentional preparation for the following year ; but it is 

 most probable that this view of the case would be to ascribe too much of foresight in 

 these operations. It is more likely that the cause of their being unfinished arises from 

 their encovmtcring some stratum of earth, wliich is too harsh or hard for their purpose, 

 or that- Jt is too soft and friable to be stable, and ha-\'ing discovered this fact, the bird 

 makes a preference of a new locality in which to have its habitation. 



The sand-martin lays from four to .six eggs, resembling those of the house-martin in 

 appearance. The nestlings are largely supported by gnats and otlier small insects, and 

 arc sometimes fed with dragon-flies almost as long as themselves. In the last week of 



* Hirundo Riparia. — Liiiii. 



