Feet and Legs 357 



We have hardly to leave the group of birds to which 

 the crow belongs to find dozens of niteresting and unex- 

 pected adaptations of the feet to unusual habits. For 

 example, the Rhinoceros-birds of Africa attach them- 

 selves to some of the larger mammals, such as buft'alos, 

 rhinoceri, or antelopes, and spend much of their time 

 in freeing these animals from troublesome ticks and other 

 parasites. The power which these birds possess in their 

 feet and legs is remarkable. Millais says of them: "The 

 prehensile power of the claws is, as I found by experience, 

 so great that when a dead bird which had grown stiff 

 was thrown on to the back or sides of an ox, so that the 

 feet touched the animal's hide, the claws held fast at 

 once and could not be withdrawn. It is most interesting 

 to note the way in which a party of these birds will move 

 about on the body of a horse or ox, searcliing every part of 

 him as they run or hop over it in the most lively fashion. 

 At the risk of being accused of telling a traveller's yarn, 

 I must state the fact that they can hop backward quite 

 as well as forward, and they often make long drops down- 

 ward from the shoulders to the foreleg, or down the side 

 of the animal whose coat they are engaged upon. It 

 is quite immaterial to them how or in what direction 

 they move." 



No hard and fast laws can be laid down, but it is gener- 

 ally the rule that birds which are especially at home in 

 the trees usually hop with both feet simultaneously 

 when on the ground. Ground nesters and feeders, such 

 as the Meadow Lark, Bob-white, and Vesper Sparrow, 

 usually walk or run. 



