CHAP. II THE ELEMENTARY FACTS OF DISTRIBUTION 15 



as Pekin, and even extends into tropical Africa, thus 

 rivalling the leopard and the wolf in the extent of country 

 it occupies. 



Of very restricted ranges there are many examples, but 

 some of these are subject to doubts as to the distinctness 

 of the species or as to its geographical limits being really 

 known. In Europe we have a distinct species of ibex 

 {Ca'pra Pyrenaica) confined to the Pyrenean mountains, 

 while the true marmot is restricted to the Alpine range. 

 More remarkable is the Pyrenean water-mole {Mygale 

 Pyrenaica), a curious small insectivorous animal found only 

 in a few places in the northern valleys of the Pyrenees. 

 In islands there are many cases of undoubted restriction 

 of species to a small area, but these involve a different 

 question from the range of species on continents where 

 there is no apparent obstacle to their wider extension. 



Specific range of Birds. — Among birds we find instances 

 of much wider range of species, which is only what might 

 be expected considering their powers of flight ; but, what 

 is very curious, we also find more striking (though 

 perhaps not more frequent) examples of extreme limita- 

 tion of range among birds than among mammals. Of the 

 former phenomenon perhaps the most remarkable case is 

 that afforded by the osprey or fishing-hawk, which ranges 

 over the greater portion of all the continents, as far as 

 Brazil, South Africa, the Malay Islands, and Tasmania. 

 The barn owl {Strix flammea) has nearly as wide a range, 

 but in this case there is more diversity of opinion as to the 

 specific difference of many of the forms inhabiting remote 

 countries, some of which seem undoubtedly to be distinct. 

 Among passerine birds the raven has probably the widest 

 range, extending from the arctic regions to Texas and New 

 Mexico in America, and to North India and Lake Baikal 

 in Asia ; while the little northern willow-wren {Phylloscopus 

 horealis) ranges from arctic Norway across Asia to Alaska, 

 and southward to Ceylon, China, Borneo, and Timor. 



Of very restricted continental ranges the best examples 

 in Europe are, the little blue magpie {Gyanopica cooJci) 

 confined to the central portions of the Spanish peninsula ; 

 and the Italian sparrow found only in Italy and Corsica. 



