INTRODUCTION 



THE idea of making a scientific investigation of the 

 various features of bird-song first occurred to me in 

 the year 1881, on the occasion of my listening to a 

 nightingale near Stroud. I observed the frequent 

 utterance of a little slurred whistle at the com- 

 mencement of many of its songs a whistle which 

 I knew to be uttered by several of its congeners ; 

 and the songs themselves often seemed to include 

 a repetition of the notes of birds of other genera 

 with which I was acquainted. I had never read 

 anything particular about the songs of birds, but 

 was aware of the imitativeness of many musical 

 species when in captivity, and I was acquainted 

 with the notes of most of the wild birds found in 

 Gloucestershire. I listened to this nightingale, at 

 the distance of a few yards, on eighteen out of the 

 twenty-one evenings on which he sang. His nest 



