HOPPERS AND WALKERS 15 



extreme, but in most running birds the hind toe 

 is absent or greatly reduced, and useless, so that 

 the case of the Ground-Hornbills, Larks, Desert- 

 Choughs (Podoces), and other running members of 

 perching groups is unique, as they alone of all 

 running creatures have the bearing-surface of the 

 foot well developed behind as well as in front. 



Unfortunately for our explanation, the Hornbills 

 and passerines do not exhaust the list of groups of 

 birds in which some members run and others hop ; 

 and in the other cases it is difficult to assign a reason 

 for the difference of gait. Pigeons, except some 

 (not all) of the most terrestrial kinds, are all short- 

 legged, and most live largely in trees, but they 

 nearly all walk, although some of the most arboreal 

 Fruit-Pigeons do hop as well ; I have seen this 

 most in the Lilac-crowned Fruit-Pigeon (Ptilopus 

 coronulatus). Parrots, again, are mostly tree-birds, 

 and all short-legged, some very much so, but they 

 generally walk, although the Lories form an excep- 

 tion by hopping. Kingfishers do not move on 

 their feet at all if they can help it, and all without 

 exception are very short on the leg ; yet the great 

 Australian Laughing Jackass, which is more of a 

 ground-feeder than any other, is a hopper, while 

 the few others I have been able to study all walk, 

 or rather waddle. So do Bee-eaters, at least the 

 Australian and European species (Merops ornatus 

 and M . apiaster) ; but of two Indian kinds of 

 Nightjars I have seen one walk and the other hop, 

 and the only Trogon (Prionotelus Umnurus) whose 



