%4 OXFORD : SPRING KSO EAELT SDMMEK. 



jauch alike in every respect but their voices (whioli though 

 monotonous are very different from each other), that it is almost 

 impossible for a novice to distinguish them unless he hears 

 them. 



Thirdly, the two species belonging to the genus Aerocephalits, 

 the Sedge- and Eeed-warblers, differ from the other two groups 

 in frequenting the banks of rivers and streams much more 

 exclusively, where they climb up and down the water-plants, 

 as their name suggests, and build 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 anyone who wiU 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 distin- 

 guishing 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 com- 

 munication : — ' 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 out the 

 three different species of Willow-wrens, which he says he has dis- 



