90 MOUNTAIN FAUNAS 



sharp bill to pick out its prey just as a butterfly uses 

 its proboscis to suck up nectar. In the Alps another 

 frequent bird is the rock-thrush {Monticola saxatilis), 

 a brightly coloured bird, extending up into the barren 

 regions of the mountain sides. In the Alps and Pyre- 

 nees also the Alpine accentor (Accentor collaris) is 

 common. With the exception. of the hedge-sparrow, 

 most of the accentors are mountain-haunting birds, 

 having strong feet and legs, which fit them for pro- 

 gression over rough groimd. Of the summer visitors to 

 the Alps, we may note the Alpiae swift (Micropus 

 melba), which is larger than the common form. 



Reptiles do not appear to show any special adapta- 

 tions to mountain life. It is remarkable that the 

 common viviparous lizard (Lacerta vivipara) ascends 

 to a height of 10,000 feet in the Alps, but then this 

 hardy animal also extends into Siberia. The common 

 viper (Pdias berus) also occurs in the Alps, though not at 

 such a great elevation, and it has a similarly wide range. 



As regards amphibians, there is some evidence that 

 the mountain habitat tends to produce darkening of 

 the colour. Thus the common frog (Rana temporaria) 

 occurs in the higher parts of the Alps ia a dark-coloured 

 variety, and the same thing is said to be true of the 

 common toad {Bufo vulgaris). Similarly the Alpine 

 salamander (Salamandra atra) is black in colour, and 

 unspotted, thus differing markedly in colour from its 

 allies. This form shows a peculiar adaptation to life 

 at considerable elevations, in that it only produces two 

 young at a time, and these pass through the giUed stage 

 within the body of the mother, so that at birth they 

 are lung-breathers like the parents, and not gill-bearing 

 tadpoles. As the animal ascends to an elevation of 

 9,000 feet, it is obvious that ice-free water for the 



