﻿Legs and Feet of Birds 



53 



birds have such elongated claws on their rear toes? Perhaps the fact that 

 these birds live almost entirely on the ground may have something to do with 

 this peculiarity. Any one who has kept a cage of small birds will have learned 

 the fact that the claws of birds are continually growing. In a remarkably 

 short time their claws become long and curved ; and in a neglected aviary I 

 have seen birds prisoners on their own perch, unable to untwist their claws 

 from it. When wild, birds wear down these claws by constant rubbing, and 

 if given plenty of rough bark and wood in their cages, their claws will remain 

 of normal length. 



Some species of swifts have all four toes pointing forward, forming a 

 four-tined grapple by which they hang themselves up in their hollow nest- 

 ing trees. Whippoorwills have a curious comb, or pecten, along the edge of 

 the middle claw, which is perhaps of use in 

 cleaning the long bristles about their mouths, 

 or in arranging their very delicate, soft plu- 

 mage. Kingfishers make so little use of their 

 feet, that not only are the toes small and 

 weak, but two of the front ones have grown 

 together for over half their length. 



Perhaps the most interesting condition 

 of toe structure is found among Wood- 

 peckers, Parrots, Cuckoos and Owls. In 

 these groups we find a similar plan of gen- 

 eral arrangement, — two toes in front and 

 two behind. With few exceptions it is the 

 great, or first toe and the fourth, or outer 

 toe which are reversed. This arrangement 

 is known as yoke -toed, or zygodactyl. 



We have seen that in perching birds the 

 arrangement is three toes in front and one behind; and now, turning to 

 the Woodpeckers, we are impressed with the wise provision made by Nature 

 for these climbing birds, — their toes spread out so that they point almost 

 to the four points of the compass, thus forming an incomparable grapple 

 or vise, which makes a vertical position as safe for a Woodpecker as a hori- 

 zontal one for a percher. 



Woodpeckers, the world over, have feet and toes which are remarkably 

 alike; but in Canada and the more northern parts of our own country there 

 are two Woodpeckers which are almost unique among the birds of this order 

 in possessing but three toes. For some reason, as yet unknown, their first 

 or great toe, which in all other Woodpeckers points backward, has vanished, 

 leaving no external trace, and the outer toe is reversed to take its place. 

 In such a fashion does Nature occasionally upset our hard -worked -out 

 theories, leaving us confused and baffled before her inexplicable surprises. 



FOOT OF CHUCK-WILL'S-VVIDOW, 

 SHOWING COMB ON TOE-NAIL 



