THE WAGTAILS 255 



wagtail, more in the grey one, whilst in the yellow and pied species 

 not many would seem to have heard it, and those who have, but 

 rarely. That this may stand in some relation with an increasing 

 beauty and nuptial display of the plumage, does not seem impossible. 

 There is, however, an alternative explanation which is equally inter- 

 esting. Is a new song, in combination with such display, in course 

 of development ? 



Independently of the spring and autumn migrations, which are 

 to be witnessed yearly on various parts of our coast, wagtails, like so 

 many other birds, flock after the nesting season is over, though this 

 phase of their life is not seen to so great advantage in these islands 

 as on various parts of the Continent. It is at roosting time, more 

 particularly, and in relation to this part of the day's routine, that the 

 social instinct is most marked. Thus Naumann 1 has given us a 

 lively picture of the way in which the white-wagtails repair, in 

 numbers, just after sunset, to the common dormitory amongst the 

 reed-beds, where, for a considerable time in fact until night has 

 fully closed in they quarrel, not only with each other and the blue- 

 headed-wagtails, who also resort there, but even such is their 

 outrecuidance with the starlings for they too like roosting in reed- 

 beds. They are now extremely noisy, singing " from full throat " in 

 such a manner as to express the angry rather than the tender 

 emotions, a use to which song is very frequently put, as may be seen 

 even with the nightingale, when two males, in the presence of a 

 female, after a few moments of rising musical fury, dash violently at 

 one another. My own view, indeed, is that it is out of the angry 

 scolding of rival males that the " music of the grove " has arisen. 

 Similar assemblages of the pied- and yellow-wagtails have been, from 

 time to time, observed in this country. A certain H. G. T., for 

 instance, writing to the Field of 26th October 1901, says : " For the 

 last two years, or more, several hundred pied-wagtails have been in 

 the habit of roosting in a small osier-bed at the back of a cottage. 



1 Naturgeschichte der Vogel Mitteleuropas, iii. 



