334 THE BIRDS OF HELIGOLAND 



collects in a primitive kind of reservoir on the Upper Plateau, 

 this nearly always, through trickling into the ground, or by evapo- 

 ration, has disappeared by May ; hence, small birds which stay 

 here during the summer, find nowhere water for drinking or bath- 

 ing, and have to fall back upon the dew of the early morning, 

 which is itself but of rare occurrence. 



A pair of these birds, some years ago, by their call and general 

 bearing, gave evidence of their intention to nest on the island ; 

 accordingly I kept a large dish constantly filled with water in my 

 garden, and had the pleasure of seeing at first the old birds, and 

 afterwards the grown-up young, daily drinking and bathing in it. 



The White Wagtail occurs as breeding species from the Pyrenees 

 to Lake Baikal. 



146. Pied Wagtail [TRAUEK-BACHSTELZE]. 

 MOTACILLA LUGUBRIS, Temmmck. 



Heligolandish : Swart-rogged ~Lungen. = Black-backed Wagtail. 

 Motacilla Yarrelli. Naumann xiii.; Blasius, Nachtrage, 114. 

 Pied Wagtail. Dresser, iii. 239. 



Bergeronnette lugubre. Temminck, Manuel, i. 253, iii. 75. 



Of the small species of insect-eating birds this beautiful Wagtail 

 is the first to commence the spring migration, as soon as winter has 

 disappeared. The earliest arrivals appear almost regularly at the 

 end of February, and fine males in full adult plumage have been 

 repeatedly killed on the 24th of the month. 



The White Wagtail, invariably, does not make its appearance 

 until a few weeks later ; and at the time when its migration is at 

 its height, that of the Pied Wagtail has already almost ceased, its 

 migration rarely extending beyond March. Strange to say, this 

 bird is hardly ever met with here during its return movement in 

 autumn ; many years ago I obtained a fine old example in winter 

 plumage, and since that time young autumn birds have been shot 

 on three or four occasions only. 



This Wagtail offers the most excellent material for observing 

 the change of colours in the plumage by re-coloration without 

 moulting any of the feathers, characteristic of many birds during 

 spring, inasmuch as it displays distinctly two out of the many 

 different ways in which this process is accomplished. The feathers 

 of the back of this bird turn at this season from a dull grey 

 to a brilliant silky black, and the snow-white portions of the 

 throat and neck likewise assume a pure and brilliant black colour. 



