50 NATURAL HISTORY 



skirmish ; and when they move from one 

 place to another, frequently turn on their 

 backs with a loud croak, and seem to be 

 falling to the ground. When this odd 

 gesture betides them, they are scratching 

 themselves with one foot, and thus lose 

 the center of gravity. Rooks sometimes 

 dive and tumble in a frolicksome manner ; 

 crows and daws swagger in their walk ; 

 wood-peckers fly volatu undoso, opening and 

 closing their wings at every stroke, and so 

 are always rising or falling in curves. All 

 of this genus use their tails, which incline 

 downward, as a support while they run up 

 trees. Parrots, like all other hooked- 

 clawed birds, walk awkwardly, and make 

 use of their bill as a third foot, climbing 

 and descending with ridiculous caution. 

 All the gallince parade and walk gracefully, 

 and run nimbly ; but fly with difficulty, 

 with an impetuous whirring, and in a 

 straight line. Magpies diVid jai/s flutter with 

 powerless wings, and make no dispatch ; 

 herons seem encum.bered with too much 

 sail for their light bodies ; but these vast 



