THE KIWIS 2341 



THE KIWIS 

 Family 



As the ostriches are the most specialized of the living members of the subclass, 

 so the kiwis of New Zealand may be regarded as those of its members which 

 occupy the most generalized position in the group. The specialization of the 

 ostriches is shown, among other features, by the gigantic stature of those birds, by 

 the reduction in the number of the toes, and in the total absence of any trace of a 

 bony bridge at the lower end of the tibia. The kiwis, on the other hand, exhibit 

 their more generalized nature by their comparatively-small size, it being obvious 

 that if the Ratites are derived from flying birds, the intermediate forms must have 

 been small, by the presence of four complete toes, and by remnants of the bony 

 bridge at the lower end of the tibia. Whether the long beak of the kiwis is also a 

 generalized feature may be doubtful. If these birds have any close affinity with 

 the tinamus, it cannot be thus regarded; but if, as some think, they are allied to 

 the rails, then it may be looked upon in this light. The kiwis, then, differ from 

 all the other living members of the subclass by their small size, the presence of 

 four toes to the foot, and the long and slender beak. They are further character- 

 ized by the females being much superior in size to the males, and also by the com- 

 plete absence of aftershafts to the feathers, while the skeleton lacks any trace 

 of the furcula. The bones of the wing especially the humerus are very 

 small and slender; and externally the whole wing is completely concealed by 

 the plumage of the back. In general appearance the entire plumage is markedly 

 hair-like, the individual feathers being pointed, and composed of separate filaments 

 toward the end of the shaft, of which the basal half is downy. In build, the kiwis 

 are very robust, the thighs and legs being very muscular and strong, while the toes 

 are furnished with strong claws. While in old birds the scales investing the meta- 

 tarsus have overlapping edges, and form a perfectly smooth surface, in the young 

 they are soft, detached, and reticulated. The general color of the plumage is 

 mottled gray and brown, the feathers having in some cases light colored shafts, and 

 in others dark crossbars. In addition to great individual variations of size, kiwis 

 are remarkable for their very large eggs, which are of a creamy-white color, and 

 out of all proportion to the dimensions of the birds by which they are laid. In hav- 

 ing the nostrils placed at the tip of the beak, the kiwis are unique. 



At the present day kiwis are represented by three or four species, of which 

 the first made known to science was the South island kiwi {Apteryx australis). 

 This species is of large size and stout build, with a very long beak; the general 

 color of the plumage being lighter, and the individual feathers of a sandier and 

 more grayish-brown tinge than in the next form. In the North island kiwi (A. 

 mantelli} the general color of the plumage of the upper parts is dark rufous streaked 

 with blackish brown, while the under parts are pale grayish brown; the streaky 

 appearance of the upper surface being caused by each feather having the middle 

 lirue pale rufous brown, darker toward the tip, and the long hair-like filaments 



