134 SWALLOW AND SWALLOW-LIKE BIRDS. 



of the insect-food to be caught flying above it ; but 

 unless the weather be inclement, he is by preference a 

 bird of the upper regions of the air, where he is no 

 doubt seriously enough employed, albeit his wild, 

 erratic flight leaves upon the observer the impression 

 that his days are spent in airy sport. Although often 

 to be seen in small parties on the wing, or in larger 

 ones drawn together by a congestion of insects in 

 some particular spot, Swifts do not swarm to roost or 

 for migration as is usual with birds of the Swallow 

 kind. They withdraw quietly during August. 



SWALLOW — 7i inches ; white below, except chin and 

 breast ; tail deeply forked. Note, ' Wheel I wheet I ' 



HOUSE-MARTIN— 5J inches; white below and on the 

 lower back. Note, ' Pri ! ' 



SAND-MARTIN — 5 inches ; mouse-brown above ; white 

 below, except cheeks and breast-band, which are mouse- 

 brown. Note, a guttural sound. 



