FEET OF CLIMBING BIRDS. 269 
pecially adapted for grasping such objects. The 
feet of some, indeed, show an utter incapacity for 
walking, and probably even for standing upon the 
ground; such a structure is seen in the kingfishers, the 
bee-eaters, the trogons, and even the puff-birds, whose 
feet have a very peculiar structure: the anterior, or 
fore toes, are united together for nearly half their 
length, so as to forma greater breadth of surface on 
their soles, by which means, although they are 
deprived of all power to walk, they are better able 
to support themselves, as they do for hours, sitting 
almost motionless on a dry twig, watching for 
insects. 
(184.) The most striking modification, however, 
of the perching structure of foot, is seen in the 
climbing birds; whose habits require that they 
should be possessed of a much firmer grasp than 
usual. Now this has been effected by the toes 
being placed in pairs, two forward and two backward, 
so that the counteraction of force becomes per- 
fectly equal. The parrots, the woodpeckers, the 
toucans, and the cuckoos, are all distinguished by 
this sort of foot; which, while it enables them to 
climb with greater facility than any other birds, 
proportionally disqualifies them, as a necessary 
consequence, from walking with readiness upon the 
sround. How nimbly and how gracefully will a 
tame parrot, for instance, ascend and descend the 
wires and perches of his cage; yet open the door, 
and place him upon the ground, or a flat surface, 
and he becomes one of the most awkward and 
clumsy of all birds: he waddles, rather than walks, 
and appears as much out of his natural element as 
