Division of Warblers. 43 



a cup-shaped nest ; and also in the nervous 

 intensity and continuity of their song. 



These eight species, then, are the 'warblers,' 

 of whom I am going to speak in the first place. 

 They may easily be remembered in these three 

 groups by any one who will take the trouble to 

 learn their voices, and to look out for them when 

 they first arrive, before the leaves have come out 

 and the birds are shy of approach on account of 

 their nests and young. But without some little 

 pains confusion is sure to arise, as we may well 

 understand when we consider that a century ago 

 even such a naturalist as White of Selborne had 

 great difficulty in distinguishing them ; he was 

 in fact the first to discover the Chiff-chaff (one 

 of our commonest and most obvious summer 

 migrants) as a species separate from the others 

 of our second group. To give an idea of the 

 progress Ornithology has made during the last 

 century, I will quote Markwick's note on White's 

 communication : ' This bird, which Mr. White 

 calls the smallest Willow-wren, or Chiff-chaff, 

 makes its appearance very early in the spring, 

 and is very common with us, but I cannot make 



