CURSORIAL BIRDS 



207 



thereby enabled to run with greater steadiness and surety. (Compare 

 the waddling gait of the duck, in which bird the legs are articulated at 

 the posterior end of the body.) 



(c) As in the case of fast-running species among mammals (horse, 

 gazelle, etc.), the toes are few in number, viz., two. They are provided 

 with broad soles, whereby the bird is prevented from sinking in the 

 sand. The inner one of the two toes is especially large, and provided 

 with a hoof-like nail (for firm application against inequalities of the 

 ground). The upper surfaces of the toes and the anterior surface of the 

 tarso-metatarsus are covered with large horny shields or plates, all the 

 other parts of the leg with a stout integument. By these provisions the 

 legs are rendered insensible to the sharpness and heat of the desert sand. 

 As in the camel, there is a horny callosity upon the middle of the breast. 

 (What is its meaning ?) 



(d) While running fast, the long-legged bird uses its wings as 

 balancing rods. It has also been noticed to employ them as aerial oars, 

 and in a favourable wind as sails. 



4. In correspondence with the height of the leg, we have the great 

 length of the neck (for the purpose of reaching the ground; compare 

 with giraffe and camel). Head and neck are scantily covered with 

 bristle-like feathers. 



5. In consequence of the length of its legs and neck, the bird, with its 

 sharp, far-sighted eyes, is enabled to survey a vast extent of ground, and 

 hastens off as soon as it catches sight of an enemy (a man, or one of the 

 feline beasts of prey). For this reason also the timid zebra likes to 

 associate itself with the ostrich, thus taking advantage of the height of 

 the bird's head, which enables it to act as sentinel. 



C. Family Life. 



A single male and several females constitute an ostrich family (see 

 domestic fowl). The females at the beginning of spring (why at this 

 time ?) lay one by one up to thirty eggs into a common nest, which is 

 nothing more than a hole scratched in the ground. The weight of each 

 egg is equal to that of about twenty-four hen's eggs. Keeent observers 

 state that the hen sits on the eggs in the day-time, the cock at night. 



The young (who are " precocious ") are protected with self-sacrificing 

 affection by their parents, especially the male birds, who will attack even 

 hyaenas, foxes and jackals in their defence. With its feet the ostrich 

 delivers blows which may prove dangerous even to man. (Compare 

 with horse.) 



