BRITISH WARBLERS 



neighbourhood. ~~ Nearly all the migrants are thus affected. 

 Hedgerows are demolished and osier-beds cleared, acres of 

 reeds are cut down and beds of rushes mown ; and bearing this 

 in mind, how is it possible for us to conceive of the same male 

 and female meeting year after year except in a limited number 

 of cases ? A male arrives at its former breeding haunt, finds it 

 unsuitable, and passes on in search of a new home ; a week 

 later his former companion arrives on a similar errand, but in 

 what a hopeless position, if just that one particular male is her 

 ultimate goal ; Nature's purpose would surely be better ful- 

 filled if she seized the first opportunity of pairing. 



The male Willow Warblers, like the males of other migra- 

 tory species, seem to arrive at their breeding ground for the 

 most part during the night, and to sing the morning after 

 their arrival. In the earlier part of the season the frequency 

 with which they utter their song is, to some extent, influenced 

 by the weather. If it is cold they are more silent and by no 

 means so active, but under ordinary conditions they sing 

 incessantly during the first few hours of daylight. They 

 search for food in their territories, travelling first in one direc- 

 tion and then in another, sometimes high up in the topmost 

 branches of such trees as oak or ash, at other times in the 

 undergrowth or bushes, and yet again upon the ground or 

 even along the banks of a stream, uttering their plaintive song 

 at intervals. When sufficient food has been found they resort 

 to some branch, often at a considerable height from the 

 ground, and there preen their feathers. In some cases one 

 particular tree seems to be especially favoured, and to con- 

 stitute the headquarters of the territory, from which excur- 

 sions are made in different directions within the domain. 



Previous to the arrival of a female excitement may be 

 caused either by the question of territory, that is to say, by one 

 male intruding upon another's ground, or by the presence of 

 a pair of Chiff-chaffs who happen to have taken up their 

 habitation in the same territory. In the first of these cases 

 there ensue frequent pursuits or conflicts ; and although such 



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