ALPINE SWIFT. 187 



against a wall or perpendicular rock, they exhibit great faci- 

 lity in preserving their equilibrium. By means of their 

 strong claws, they cling firmly on ; and their tails serve them 

 as a rudder or a rest, wherewith they balance themselves so as 

 to be enabled to move the upper part of their body in any 

 direction they may require. The position of the bird repre- 

 sented in our plate has been chosen for the purpose of eluci- 

 dation. 



In constructing their nests the Alpine Swifts make use of 

 their power of clinging in the manner described, in order to 

 place their nests in situations inaccessible to interruption. They 

 choose for their breeding-places cracks and fissures in rocks, 

 and holes in walls of lofty construction ; and soon after their 

 arrival in Europe either resort to an old habitation of their 

 own, or select a new one, and begin to prepare the nest, 

 which is composed of dried grass, straw, dead leaves, wool, 

 and feathers, all heaped on one another without order or 

 arrangement ; and the whole is said to be glued together 

 by means of saliva from the bird's mouth, which dries very 

 fast, and gives it the appearance of having been varnished. 



Towards the end of May, the female lays two or three 

 singularly-shaped eggs, much resembling those of the Common 

 Swift, but larger, which are hatched after fourteen days 

 incubation. The young, when able to fly, follow the parent 

 birds, but continue for some time to receive food from them 

 on the wing Towards the end of August, young and old 

 take their departure together, and disappear generally all 

 in one night. Where these birds are plentiful they are 

 caught for the table, their flesh being considered very ex- 

 cellent. 



Their call-note is skree, skree ! and resembles that of 

 the Common Swift, but is more musical, and almost as strong 

 as the cry of the kestril. 



The measurements of the Alpine Swift are as follows : 



o 2 



