BRITISH WARBLERS 



circumstances, and this shyness continues throughout the whole 

 period of reproduction. If I cut away the undergrowth and 

 make a clear opening so as to be able to observe them at the 

 nest, I find that they have difficulty in overcoming their 

 natural timidity. Only when one stands some distance away 

 can they be persuaded to approach the nest, and this distance 

 requires to be much greater than is necessary in the case of 

 the Eeed Warbler. During incubation it is impossible to be 

 too careful in taking up one's position, and even when a post 

 from which observations can be taken has been successfully 

 reached, it is essential that little or no movement should be 

 made if suspicion is not to be aroused. I am inclined to 

 doubt whether the birds really become reconciled to the 

 human presence after the young are hatched, for it will be 

 noticed that they then carry out their duties hurriedly, over 

 anxious apparently to finish the task they have in hand. One 

 of the sexes is more timid than the other, though it is difficult 

 to determine which, but since in the case of the Eeed Warbler 

 it is the male that is the more nervous, it is probably the 

 male that lacks courage in this species ; all this timidity tends 

 to show that the temperament of the bird is different from 

 that of the Eeed Warbler, and it is interesting to note that 

 the greater timidity seems to be correlated with a greater 

 nervous development in other directions. It may here be 

 mentioned that the male, when approaching the nest in order 

 to relieve his mate, sometimes utters a few phrases of his song, 

 and also that the presence of a Eed-backed Shrike (Lanius 

 collar io) near the nest seems to cause him much anxiety, 

 which he shows by moving restlessly to and fro and vigorously 

 uttering his scolding note so long as it remains in the 

 vicinity. 



There is considerable variation in the length of time that 

 the young of different pairs remain in the nest. Development 

 appears to be more rapid in one case than in another. One 

 nest will be deserted at the end of ten days, whereas another 

 will still be a nursery at the end of fourteen. Ten days is 



50 



