270 STUDY OF NATURAL HISTORY. 
is a swan upon dry land. True it is that all parrots — 
are not so formed; or rather there are some which, 
still possessing the same character of feet as those 
just mentioned, have them so modified and altered, 
that they can not only walk with perfect ease, but 
habitually frequent the ground in preference to 
other situations. It is curious and instructive to 
see how nature has effected the difficult object of 
giving to a scansorial foot the facilities of a walking 
one, without impairing the essential character of 
the family to which these ground parrakeets belong. 
On looking to the feet of the generality of parrots, 
it will be observed that the claws are particularly 
strong, broad, and well curved; so that when the 
foot is placed upon the ground, the tips of the 
claws touch, or come in contact with, its surface. 
Now much walking would soon wear away their 
points, as we see it does in those of gallinaceous 
birds ; and this, to birds which climb, and use their 
claws for that purpose, would be a serious injury. 
But on examining the foot of a ground parrakeet 
( Pezoporus formosus Ill.), we see, indeed, the same 
general disposition of the toes; that is, two before, 
and two behind; but the legs are higher, more 
slender, and therefore better adapted for walking: 
the claws, moreover, are formed upon quite a dif- 
ferent principle ; instead of being thick and hooked, 
like talons, they are long, slender, and very slightly 
curved, so that when the bird walks, or (as we 
suspect) runs, on the ground, the points do not 
come into contact with the surface, which they un- 
questionably would do were their curve greater 
than it really is. From this peculiar conformation 
