WILLOW WARBLER 



have already mentioned that the habits of the Willow 

 Warbler and those of the Chiff-chaff are so similar that it 

 is well-nigh impossible to distinguish between them in actual 

 life. This is true of their habits as a whole, but the expression 

 of sexual emotion differs considerably, and it is possible to 

 recognise the peculiar wing-flapping of the Willow Warbler 

 at some distance. This wing-flapping is not confined to 

 one sex only, but forms part, though a lesser part, of the 

 sexual manifestation of the female. It can be seen to the 

 best advantage — for the peculiarity is then more striking — 

 when both sexes perform at the same moment, an occur- 

 rence by no means unusual. Settling a few feet apart, they 

 face this way or that, often in opposite directions, and 

 standing in an upright position on the branch, partially 

 extend their wings, and flap them at a moderate speed. 

 Whilst thus performing they carry their heads rather high, 

 slightly expand their tail, and become so completely absorbed 

 in their performances, which may last for fully half a minute, 

 that they take little or no notice of one another. At this 

 period during the first few hours of daylight the wing-flapping 

 is of frequent occurrence on the part of one sex or the other ; 

 and when a number of territories adjoin and a female is present 

 in each one of them, this curious but interesting behaviour 

 can be observed with but little difficulty. Even when the 

 female is not in his immediate presence, the male may be 

 seized with sexual emotion and express it in this manner. 

 In its details the performance varies but little, the wings are 

 not always expanded to a similar extent, and the tail is 

 sometimes slightly raised. Silence is often maintained, but 

 may be replaced by a highly pitched twittering sound uttered 

 in sympathy with the bodily movement. Although apparently 

 so absorbed when performing alone, it is quite clear that the 

 male is very much on the alert and knows the whereabouts 

 of the female, for in the midst of his emotion he will dart off" 

 without hesitation towards her, when the usual fluttering of 

 wings and rapid pursuit follow. 



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