178 BIRDS OF THE WORLD 



places, where he struts or pirouettes with erect tail 

 and drooping wings, scratching, pecking, and singing 

 at intervals. The normal cry is a loud, liquid 

 gurgling sound; but they are clever mockers, imitat- 

 ing a cock's crow, a hen's cackle, a dog's bark or howl, 

 the Laughing Jackass's note, or even the setting of a 

 saw." They lay but one egg, in a bulky nest of sticks, 

 lined with moss and feathers, and placed either in the 

 fork of a tree or on the ground. The nestling is 

 remarkable for the fact that it is covered with long 

 and woolly down — a feature shared by no other 

 Passerine bird. 



All the birds now left for consideration here belong 

 to the second section, and are commonly called the 

 true Oscines, having from five to seven pairs of 

 singing-muscles. 



These will be described in order, as nearly as 

 possible, according to their grade of evolution. That 

 is, we shall begin with those species which are appar- 

 ently least specialised, least modified, and proceed to 

 those which are most specialised, or modified. 



Swallows 



According to this plan, we commence with the 

 Swallow tribe. There are many species of these birds, 

 widely distributed throughout the world. All have 

 long, slender, but powerful wings, and very weak 

 feet, showing that much of their life is spent in flight 

 and that the feet have become feeble from disuse. In 

 many species the tail is forked. They feed almost 

 entirely upon insects, captured in the air, their deeply 



