2220 THE BUSTARDS, THlCKNEES, AND CRANES 



present either the breastbone has no notch, or the oil gland is naked; while from 

 both the pigeons and sand grouse they are separated by the upper end of the hume- 

 rus being of normal form; the condition in which the young are born also forming 

 a point of distinction between the former of those two groups. Briefly, then, the 

 Alectorides may be approximately defined as including those schizognathous birds 

 with active young,* in which the humerus has no process at the lower end, and the 

 angle of the lower jaw is truncated; the nostrils being either schizorhinal or holo- 

 rhinal, but, when the latter, either the number of the toes is reduced to three, or the 

 sternum is entire, or the oil gland naked ; the upper end of the humerus being always 

 of normal form. Such characteristics may seem not only trivial, but in some cases 

 difficult to understand, although, when dealing with groups of such nearly-allied 

 birds, they are almost the only ones available. Like the orders treated in the two 

 preceding chapters, the members of this group either have the toes free, or but par- 

 tially connected by webs. 



THE BUSTARD TRIBE 

 Family OTIDID^ 



The stoutly-built birds known as bustards and floricans agree with the rails in 

 having the nasal openings in the skull of an oval shape (holorhinal); but they differ 

 in having only three toes to each foot, and likewise in the absence of bare tracts in 

 the plumage of the sides of the neck, and of an oil gland. In their skeleton the 

 breastbone has two notches in its hinder border, and the furcula is U-shaped. Ex- 

 ternally they are characterized by the relatively-short beak, in which the oval nos- 

 trils are placed near the base; the stout and moderately -long legs, in which the 

 metatarsus is shorter than the tibia; the long wings, and the short tail; the number 

 of primary quills being ten, and that of the tail feathers twelve. They undergo a 

 complete molt in autumn, and often a partial one in spring; and the plumage of the 

 two sexes may be nearly similar, or considerably different. The bustards are con- 

 fined to the Old World, where they are represented by between thirty and forty 

 species, of which a considerable proportion are natives of Africa south of the Sa- 

 hara. Essentially terrestrial birds, and chiefly inhabitants of open plains and 

 steppes, the bustards are admirably adapted for running and walking, although they 

 are likewise powerful and rapid in flight. Their mottled plumage of brown, black, 

 and gray harmonizes with the coloration of their surroundings. In some the food is 

 chiefly vegetable, although supplemented by insects and reptiles, but in others it 

 consists mostly of animal matter. 



The great bustard ( Otis tarda) , which formerly inhabited many of 



the wilder, open districts of Britain in large flocks, is the type of a 

 Bustards . . . 



genus which may be taken to include two species, and is characterized 



by the shortness of the beak and the absence of a crest on the head. The legs are 

 relatively short, with a small portion of the tibia bare, and the metatarsus (as in 



* In the sun bittern, the young are helpless, while those of the kagu are unknown. 



