282 PALLAS' DIPPER. 



is impermeable to water, as much so as that of the most decidedly 

 aquatic -web-footed birds, for when dipped into it, that fluid runs and 

 drops from the surface. Their head is flat, with the forehead low and 

 narrow ; the neck is stout ; the body short and compact ; the nostrils 

 basal, concave, longitudinal, half covered by a membrane ; tongue car- 

 tilaginous and bifid at tip. Their wings are short and rounded, fur- 

 nished with a very short spurious feather, and having the third and 

 fourth primaries longest ; the tail short, even, and composed of wide 

 feathers ; the nails large and robust ; the lateral toes are subequal, the 

 outer united at base to the middle one, the hind toe being short and 

 robust. The female is similar to the male in color, and the young only 

 more tinged with reddish. They moult but once in the year. 



These wild and solitary birds are only met with singly or in pairs, in 

 the neighborhood of clear and swift-running mountain streams, whose 

 bed is covered with pebbles, and strewed with stones and fragments of 

 rock. They are remarkably shy and cautious, never alight on branches, 

 but keep always on the border of the stream, perched, in an attitude 

 peculiar to themselves, on some stone or rock projecting over the water, 

 attentively watching for their prey. Thence they repeatedly plunge to 

 the bottom, and remain long submerged, searching for fry, Crustacea, 

 and the other small aquatic animals that constitute their food. They 

 are also very destructive to musquitoes, and other dipterous insects and 

 their aquatic larvse, devouring them beneath the surface. They never 

 avoid water, nor hesitate in the least to enter it, and even precipitate 

 themselves without danger amidst the fails and eddies of cataracts. 

 Their habits are in fact so decidedly aquatic, that water may be called 

 their proper element, although systematically they belong to the true 

 land birds. The web-footed tribes swim and dive : the lonoi-lesrred 

 birds wade as long as the Avater does not touch their feathers ; the Dip- 

 pers alone possess the faculty of walking at ease on the bottom, as 

 others do on dry land, crossing in this manner from one shore to the 

 other under water. They may be often seen gradually advancing from 

 the shallows, penetrating deeper and deeper, and, careless of losing 

 their depth, walking with great facility on the gravel against the current. 

 As soon as the water is deep enough for them to plunge, their wings are 

 opened, dropped, and agitated somewhat convulsively, and with the head 

 stretched horizontally, as if flying, they descend to the bottom, where 

 they course up and down in search of food. As long as the eye can 

 follow them, they appear, while in the water, covered with bubbles of 

 air, rapidly emanating from their bodies, as is observed in some coleop 

 terous insects. 



The Dippers run very fast : their flight is direct, and swift as an 

 arrow, just skimming the surface, precisely in the manner of the King- 

 fisher. They often plunge under at once without alighting, reappearing 



