41 o The Bird 



Reserving the mention of partly ornamental tails until 

 the last, we may now consider the use of this member as 

 a prop or support to the bird as it clings to or makes its 

 way up vertical surfaces. Four groups of birds which 

 are thus distinguished are the woodhewers a tropical 



FIG. 326. Chimney Swift clinging to wall, resting upon tail. 



family, the creepers, woodpeckers, and swifts. These 

 birds really sit upon their tails, the feathers of which are 

 adapted for this special use, while retaining perfectly the 

 rudder function in flight. The tail-feathers of the Chim- 

 ney Swift are peculiar in having the ends, for a short dis- 



