I04 A BOOK OF BIRDS 



moors the eggs are laid among the heather. Usually not more than 

 six in number, on occasions as many as twelve are laid. During the 

 great vole plague, which occurred in Scotland, for example, a few 

 years ago, these birds assembled in large numbers over the stricken 

 area, and finding an abundance of food reared broods of double the 

 normal numbers, and performed this feat twice during the year ! 



The Barn Owl (Plate XX. fig, 6) is not only an extremely hand- 

 some species, but forms a group by itself apart from the rest of the 

 Owls. In its distribution it is cosmopolitan, though in parts of its 

 range it has become stationary, and has accordingly assumed more 

 or less marked differences of coloration. Like the Tawny Owl, its 

 eyes are almost black, bright orange-yellow being the colour of the 

 iris in nearly all the Owls. This bird, from its note, is often known 

 as the Screech Owl. 



The young Barn Owl is at first clothed in a downy coat of snowy 

 white, and this is replaced by a plumage indistinguishable from that 

 of the adult. In most, if not all, other Owls, however, the first 

 coat of down-feathers is replaced by a plumage exactly inter- 

 mediate between nestling-down and true feathers, and this is worn 

 till October, when it is shed and succeeded by normal feathers. 



