154 THE STORY OF THE BIRDS 



remote the connection of an island with the 

 adjoining continent the more diverse is the 

 avifauna found upon it. Another fact of special 

 interest to the student of geographical distribu- 

 tion is the enormous area occupied by some 

 species, and the remarkably restricted one of 

 others. The Barn Owl, for instance, is found 

 nearly all over the world, whilst many other 

 species of Owls are confined to a single island. 



Finally, a few words concerning the influence 

 of climate upon species. We may aptly repeat, 

 almost word for word, what we wrote many 

 years ago upon this matter : The importance of 

 climate in zoological geography is considerable, 

 although the subject has been much neglected 

 by the student when seeking to solve perplexing 

 questions of distribution. For instance, the 

 Palaearctic Region presents some of the greatest 

 contrasts of climate to be found in the world, 

 and each particular kind of climate is stamped 

 indelibly upon the plumage of the birds within 

 its influence. The extreme west, including the 

 British Islands and Scandinavia, is moist, favour- 

 able to the development of brown ; the north 

 and central districts, including Russia, Siberia, 

 and Kamtschatka, are cold and dry, and here 

 the colours are bleached and produce the arctic 



