26 LOST AND VANISHING BIRDS 



nesting and roosting in high trees, with the 

 beneficial result that its numbers are now steadily 

 on the increase again. It is gratifying to have 

 Mr. W. W. Smith's assurance that in certain parts 

 of New Zealand some of the rat-threatened birds — 

 Honey-eaters and others — are again increasing in 

 number, as conditions are proving less satisfactory 

 for their four-footed foe, and the clearing away of 

 the lower bush is depriving the rat of a favourite 

 haunt. Another fruitful cause of extinction is the 

 importation by settlers, from sentimental motives, 

 of certain birds from Europe, notably the House 

 Sparrow, which have succeeded in crowding out 

 many indigenous species. Dogs, cats, goats, and 

 hogs, when introduced into small islands, have also 

 exterminated many helpless avine species, especially 

 ground birds and those in which the power of 

 flight was limited or even absent. 



Comparatively few people are aware how 

 rapidly and upon what an enormous scale the 

 spread of civilisation is working changes and 

 making serious gaps in the fauna of the world. 

 Civilisation, wherever it spreads, sooner or later 

 affects the wild creatures of the invaded area, and 

 in most cases the change has been attended with 

 disaster to the fauna. Islands do not suffer alone. 



