256 CRAB FEET. 



their food. As they feed in the twilight, they must 

 feed in part on moths ; but that is also the time when 

 the larger coleopterous insects are on the wing ; and 

 these may require preparations for the stomach dif- 

 ferent from what are requisite in the case of the 

 naked-winged insects, which form the principal food 

 of the swallow tribe. Still, in the form of their bo- 

 dies, in the texture, and even in the colouring of 

 their plumage, the nocturnal species differ from the 

 diurnal ones much in the same way that the owls 

 differ from the nocturnal birds of prey. 



There is even a similar distinction in respect of ha- 

 bitation. The diurnal species, like the diurnal birds of 

 prey, are all dwellers in open places, and they do not 

 nestle in trees : the nocturnal ones are copse or 

 woodland birds ; and though some of them are un- 

 derstood to nestle on the ground, the greater number 

 certainly nestle in trees and bushes. Yet further : 

 the diurnal ones have a harsh, sharp scream, which 

 though not exactly like the chirrup of hawks, has 

 some resemblance to it ; and they are in general 

 silent : the nocturnal ones, on the other hand, have 

 a more continued and stridulous cry; and in the 

 depths of the tropical forests, especially those of 

 America, they keep not only the common night, but 

 the sultry and otherwise silent noon, alive with their 

 cries. 



Being all chiefly insect feeders, they are most 

 abundant in tropical climates ; and those which fre- 

 quent cold and temperate regions in the summer 

 always quit them before winter. The nocturnal 

 feeders, being birds of less firm feather and less 

 powerful wing, are by no means so migratory as the 

 diurnal ones. These last, as will be more particularly 

 shown when we come to give some account of wings. 



