THE PASSERINE BIRDS 113 



or on the ground. The nestling is remarkable for the fact that it is 

 thickly covered in long and woolly down — a feature shared by no 

 other Passerine birds. 



THE TRUE OSCINES 



All the birds now left for our consideration belong to the second 

 section to which we have just referred, and are commonly described 

 as the true Oscines, having from five to seven pairs of singing- 

 muscles. 



In describing these we shall take them in order, as nearly as 

 possible, according to their grade of evolution, so far as this can be 

 determined. That is, we shall begin with those species which are 

 apparently lowliest, or least specialised, least modified, and proceed 

 to those which are highest or, rather, most modified. 



FAMILY HIRUNDINID^ (Swallows) 



By this plan we commence with the Swallow tribe ; three species 

 of which are common during the summer months in Great Britain. 



Next to the Cuckoo, the Swallow (Plate XXI. fig. 4) is the bird 

 whose appearance in the spring is most eagerly looked for. The 

 Swallow lends a certain indefinable charm to the life of the country 

 during the summer months, and it is certainly a most useful bird. 

 Like its relative the House-martin, the Swallow builds a nest of mud, 

 which is always placed on some rafter in outhouses, sheds, and similar 

 places. And here two broods are reared before the summer is 

 passed and they leave us again, at the approach of winter, for the more 

 congenial climate of Africa. There was an old superstition to the 

 effect that Swallows passed the winter in this country in a state 

 of torpor, choosing horse-ponds and similar places in which to 

 hybernate at the bottom of the water ! 



The House-martin (Plate XXI. fig. 3) may easily be distinguished 

 from the Swallow, having a large patch of white on the lower part 

 of the back, and white under parts. Further, the legs and toes of the 

 Martin are completely covered with short, downy feathers. 



The mud nests of the Martin are familiar objects enough during 

 the summer months, being fastened to the overhanging eaves of 



15 



