186 HIRUNDIN1D.E. 



The food of the Alpine Swift consists of insects which 

 enliven the higher strata of our atmosphere, and which they 

 take upon the wing as long as daylight lasts ; as evening 

 draws in they take a lower flight, in order to feed upon 

 beetles, moths, and other night-flying insects. Their long 

 and powerful wings not only help to sustain these birds with 

 the greatest ease in the air, but their peculiar construction 

 enables them to cut, as it were, through the currents of air 

 which they must most naturally meet with during their 

 flights, particularly among the chasms of rocks where the 

 gales are of the most formidable description. 



When the atmosphere is moist and cold, and there are 

 no insects in the upper air sufficient for the support of these 

 birds, they may, under such circumstances, be seen skim- 

 ming in hurried flight over swamps, lakes, and ponds. Their 

 flight is exceedingly quick and boisterous, and in their nature 

 they are restless and turbulent, and very unsociable, except 

 with their own families. It is very remarkable, that al- 

 though these creatures are all day on the wing, their untiring 

 energy should enable them to keep up their gambols until 

 late at night, when they may be heard quarrelling together, 

 and rushing through the valleys and along the streets of 

 towns in pursuit of one another, for hours after it is dark ; 

 yet so little rest appears to suffice these birds, that among 

 the earliest risers this Swift is usually the first. It seems 

 as if the construction of the Swift is such as to enable it 

 to float on the air in the same manner as the fish supports 

 itself in the water. 



The Alpine Swifts are seldom seen to alight upon the 

 ground, and when they do so, the construction of their legs 

 and feet not being adapted for walking and perching, they 

 shuffle along and look very awkward, and the great length 

 of their wings renders it very difficult for them to rise again. 

 But when desiring to retain themselves in a hanging position, 



