The Feet of Birds. 45 



members that enables the feathered race to rest with ease in a 

 position in which other animals could not support themselves 

 for a minute ; and of which formation the true perchers afford 

 so excellent an example. The natural position of a bird's toes is 

 not, as with men's fingers, stretched out and open, but the very 

 reverse ; it requires an effort in the bird to spread open its toes, 

 just as it does in a man to close his fingers. Hence, when it 

 rises on the wing and flies through the air, the foot is doubled 

 up under the body, and the toes immediately contract, and only 

 unbend again when about to seize the bough of a tree ; hence, 

 again, when it perches on a spray, the toes, previously opened 

 for the purpose, grasp it by their natural flexion, and firmly 

 clasp the support on which they have alighted. This is a very 

 excellent adaptation of peculiar structure to the required end, 

 but in addition to this there is a most admirable piece of internal 

 mechanism, which I cannot better describe than in the words of 

 Bishop Stanley : ' Connected with the thigh-bones and leg, a cefc 

 of muscles run down to the very extremity of the toes, so con- 

 trived and placed that, when by pressure downwards the limb 

 bends, these fine muscles are pulled in, and therefore contract 

 the toes, thus making them grasp more firmly whatever the bird 

 is resting upon ; just as if a set of fine strings ran over pulleys to 

 certain hooks, and were acted upon at the other end by a weight 

 or pressure, and thereby made to draw in the hooks.' Such, 

 then, is the wonderful power given to perching birds, whereby 

 they can hold themselves securely even in sleep on so slender a 

 support. This faculty is shared in by the whole order ; but as 

 the families and genera which compose this extensive division are 

 so numerous, and obtain their food in such a variety of ways, it 

 is clear that there must be considerable varieties in the develop- 

 ment of their feet. The tribes which dwell among the boughs 

 of trees, now hanging with their heads downwards, now hurry- 

 ing along the underside of the branch, will require a foot some- 

 what differently formed from those which run on the ground 

 and perch on the topmost spray. Still, in so vast a number, 

 it will be impossible in this place even to touch upon the 



