THE DIPPER 301 



was actually greater than that element." l This may be explained by 

 the not unlikely assumption that the bird keeps a firm grasp on the 

 ground with its feet. The assumption does not, however, explain 

 the statement, made by good authorities, that it will also sink in 

 the same way, "horizontally" as Lord Lilford puts it, 2 from the 

 surface of the water, unless, of course, the latter be shallow enough 

 to permit the feet to touch bottom. This sinking from the surface 

 I have not myself witnessed ; the bird always seemed to me to dip 

 under with a slight splash. 



The excursions of the dipper beneath the surface of the water are 

 of a strictly practical nature ; it goes in pursuit of its prey, using its 

 wings to propel it to the bottom, where it manages to maintain its 

 position against, the upward impulsion of its specific gravity by a com- 

 bined effort of wings and feet. The strong claws of the latter serve to 

 hold the bird fast to the bed of the stream at each step in its progress, 

 the wings being perhaps chiefly employed in keeping the head down- 

 ward so that the beak may do its work. The course of the bird 

 is sometimes, if not always, marked by an upward stream of air- 

 bubbles, some of which cling to its body, thus giving it the appear- 

 ance of being decked with pearls. 



The use of the claws here noted is precisely what one would ex- 

 pect from a Passerine species when picking up food at the bottom of 

 the water. It would be difficult, for example, to imagine pochards 

 or other diving ducks acting in the same way, the method of the 

 latter being to keep themselves submerged, head downward, by 

 upward strokes of the webbed feet. 



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* > >* * 



The appearance of the dipper when thus " walking " in its aquatic 

 pastures has been variously described. According to a correspondent 

 in the Field, the method of progression resembles " a running flutter," a 

 phrase intended to emphasise the partial use of the wings as the bird 

 runs along. Montagu, in an oft-quoted sentence, writes that to his 



1 Montagu, Dictionary of British Birds, p. 215. 



2 Lilford, Birds of Northants, i. 85, who endorses a similar statement made in Yarrell's 

 British Birds, vol. i. p. 242. 



