BIRDS OF THE RIVER 355 



and even a third species should be admitted, this 

 view being based mainly on the fact that, in some 

 localities, Dippers are found lacking the chestnut 

 band on the breast. But this black-breasted form, 

 which also at times occurs in England, is not 

 generally held to constitute a separate species. 



Of the five species of Wagtail included in the 

 British list three only may be regarded as familiar. 

 The two rarer birds^the Blue-headed and the 

 White — were for a long time regarded as mere 

 Continental modifications (even if the differences 

 were observed at all) of the Yellow and the Pied 

 respectively. They are now admitted to be of 

 separate species, and the distinctions can easily be 

 recognized on examination. The Blue-headed Wag- 

 tail may be known at once by the bluish-grey hue of 

 the head and the white eye-streaks, as compared 

 with the pale-olive head with yellow eye-streaks of 

 the Yellow form, and the White may be dis- 

 tinguished by its ashen-grey back in marked con- 

 trast with the blacker plumes of our own Pied 

 variety. 



Two of the British Wagtails — the Pied and the 

 Grey — may be properly accounted birds of the 

 river, although the former is by no means exclu- 

 sively so. Still, one so rarely spends a day on a 

 trout-stream without seeing one or other of these 

 beautiful birds running swiftly amidst the shingle 

 or alighting upon the partly submerged stones, that 

 one comes to regard them as an integral part of the 

 scenery. 



