96 BIRDS OF LA PLATA 



ascends until it becomes a mere speck in the blue 

 zenith, the hurried zigzag flight of the pursuer, 

 rising every minute above its prey, only to be left 

 below again by a single flap of the Heron's wings, 

 forms a sight of such grace, beauty, and power as 

 to fill the mind of the spectator with delight and 

 astonishment. 



When the enemy comes to close quarters, the 

 Heron instinctively throws itself belly up to repel 

 the assault with its long, crooked, cutting claws. 

 Raptorial species possess a similar habit ; and the 

 analogous correlation of habit and structure in genera 

 so widely separated is very curious. The Falcon 

 uses its feet to strike, lacerate, and grasp its prey ; 

 the Heron to anchor itself firmly to its perch ; but 

 for weapons of defence they are equally well adapted, 

 and are employed in precisely the same manner. 

 The Heron, with its great length of neck and legs, 

 its lean unballasted body, large wings, and super- 

 abundance of plumage, is the least suited of birds 

 to perch high ; yet the structure of the feet renders 

 it perfectly safe for the bird to do so. Thus the 

 Heron is enabled to sit on a smooth enamelled rush or 

 on the summit of a tree, and doze securely in a wind 

 that, were its feet formed like those of other Waders, 

 would blow it away like a bundle of dead feathers. 



Another characteristic of Herons is that they carry 

 the neck, when flying, folded in the form of the letter 

 S, At other times the bird also carries the neck this 

 way ; and it is, indeed, in all long-necked species 

 the figure the neck assumes when the bird reposes 



