BRITAIiN^S BIRDS AND THEIR NESTS. 305 



it may be seen flitting from stone to stone in a jerky 

 manner, alighting in characteristic fashion. If we are 

 lucky we may see it exercise its remarkable power of 

 walking into and under the water. Down it walks, quite 

 unconcernedly, and moves about the bottom searching 

 for the aquatic organisms that form its food. Up it 

 comes, and shakes its plumage diy in an instant. At 

 another time it sinks from the surface where it was 

 momentarily floating. Exactly how it keeps under water 

 is a mystery, just as in the case of the self-submerging 

 of the Dabchick and other Water-Fowl. Any force that 

 is exerted vertically seems wholly inadequate to keep a 

 light body like a bird wholly under water. 



That a Passerine bird should have taken to an aquatic 

 mode of life is rather remarkable. It is yet another 

 instance of a bird modifying its habits to escape the 

 competition of allied forms, and to occupy a ' vacant place 

 in nature.' Birds of this Order exist in America which 

 have habits intermediate between those of this species 

 and those of the neighbouring Thrush family. These 

 Water-Thrushes ' wade into streams and pick out minute 

 animals from the bottom. Their plumage becomes 

 drenched, but can be shaken dry in a moment. Certainly 

 the Water-Thrushes ha\e taken preliminary steps towards 

 becoming as aquatic as the Dipper.' So writes Dr Alfred 

 Russel Wallace. 



The name ' Dipper ' is certainly both suggestive and 

 appropriate. The name 'Water-Ousel,' widely used, refers 

 to the faint general resemblance of its plumage to that of 

 the Blackbird and its near allies. The Dipper is found 

 not only on almost every Scottish 'burn,' but also on many 

 of the similar streams of Ireland, Wales, and the north 

 and south-west of England. From the lowland counties 

 of England it is practically absent, except in winter, when 



2m 



