42 Oxford: Spring and Early Summer. 



as much good as harm by a large consumption 

 of insects and caterpillars. 



Secondly, the two kinds of birds belonging to 

 the genus Phylloscopus, Chiff-chaff and Willow- 

 warbler, are alike in having slender, delicate 

 frames, with a slight bend forward as of creatures 

 given to climbing up and down, in an almost 

 entire absence of the steady perching habit, in 

 building nests upon the ground with a hole at 

 the side, and partly arched over by a roof of 

 dried grass, in feeding almost exclusively on 

 insects, and in singing a song which is always 

 the same, each new effort being undistinguishable 

 from the last. In fact these two birds are so 

 much alike in every respect but their voices 

 (which though unvarying 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 

 AcrocephaluSy the Sedge- and Reed-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 



