76 ANATOMY OF BIRD'S WING 



the wing itself. Without going too deeply 

 into anatomy, it may be briefly said that 

 the wing of a bird corresponds to the arm of 

 the human species, and that the chief bones 

 include the brachium, antibrachium and 

 manus (the hand), from which subtends, in 

 fan-like extension, the "primaries" or flight- 

 feathers ; next in order to these are the 

 " secondaries," and above, proceeding from 

 the shoulder, the scapular feathers which form 

 the wing cover. There is also a group of stiff 

 feathers attached to a small spur-hke bone 

 (the thumb) which projects from the meta- 

 carpus or wrist joint ; this is known as the 

 bastard wing. In the Spur- Winged Plover, 

 the digit terminates in a hook, and is apparent 

 outside the plumage. 



The wings of birds are curved, some more so 

 than others. The feathers overlap one another 

 and lie closely appressed, taking the same line 

 of curvature, consequently are more or less 

 bent according to their relative positions on 

 the wing. The curved shaft of each feather 

 tapers to a sharp point, which renders the 

 feathers spring-like and resilient ; thus the 

 feather is seen to bend under pressure from 

 above, but resists pressure in a contrary 

 direction. This is the nature of a single 

 feather, and the same applies exactly to the 



