HIRLNDIXrn.E. 



// 



SUB-FAMILY I. 



Cypselix.e. 



The Swifts. 



Gen. Charac. — Bill short, depressed, broad at the base, the sides suddenlj' 

 compressed to the tip, and the margins inflected ; the nostrils large and 

 longitudinal on each side of the culmen ; the wings extremely long and. 

 curved ; the tarsi short and weak ; the toes short, thick, and armed with 

 short, strong, and much-curved claws ; the hind toe usually directed 

 forwards. 



,1 ljf.^^\']] 



•; i'^^O 



Fig. 30. — the swift. 

 Cypxelug opus.) 



The Swifts are all birds of migratory habits. 

 They pass most of their days in the air, for which 

 their slender forms and powerful wings are ad- 

 mirably adapted. Their flight is rapid, performed 

 in lengthened sweeps, or in extensive curves, with 

 marvellous ease and grace. The height to which 

 they ascend is regulated by the state of the at- 

 mosphere. On fine days they fly in numbers 

 together, at a great elevation ; but during gloomy 



