3o8 



The Bird 



of blood-like scarlet in the centre of its breast? The re- 

 markable and inexplicable resemblance is heightened 

 by the stiffened vanes of the centre feathers, causing them 

 to appear bedraggled and clotted, as if by an actual wound ! 

 The photograph does but little justice to the bird's real 

 appearance. 



Another class of colours, while still protective, is so 

 for a purpose very different from those cases which we 



Fig. 215. — Bleeding-heart Pigeon. 



have been considering. The colours which we are now 

 to mention have been aptly called aggressive colours, as, 

 bj^ their means, a bird of prey is enabled to approach 

 its victim more easily. So, throughout the entire animal 

 world we find two phases of phenomena constantly pres- 

 ent: on the one hand the pursued ones, striving to escape 

 by all means in their power; and on the other hand the 

 pursuers, ever trying to outwit those upon which they 

 prey. If a duck acquires great speed of flight, the Duck 



