Mr. Bartlett quoted. 245 



concealed as they must always be in the clear, open- 

 foliaged trees planted by man." * A point this which 

 certainly deserves more special and exact working out 

 than it has yet got ; leading us, as it does, to a vast 

 problem ; to the part — the unconscious part — which 

 civilized man plays, wherever he settles or advances, 

 in gradually modifying the life and habits of all 

 creatures, and, so far as we know, more especially of 

 birds. He clears forests, and plants new kinds of 

 trees : he lays out parks, and makes ornamental what 

 before was wild : he decreases the volume of streams 

 and rivers, by turning them to account for irrigation 

 or for driving machinery, or other purposes, or to 

 supply the needs of towns, in succession to, or in 

 supplement to previous reduction, by timber cut down 

 over wide areas, and on slopes, on hill tops, thus lim- 

 iting substantially the rain-fall. The trees he plants 

 are less thick-leaved than those he has rooted out. 

 And as the face of the country changes — its whole 

 physical geography being gradually modified — so do 

 the various species of creatures change ; their habits 

 gradually modified, in obedience to the law of self- 

 preservation and increase of the species, if not to the 

 law of " Natural Selection" and "Survival of the 

 Fittest." 



Mr. Bartlett, in Wild Animals in Captivity, re- 

 marks : 



" The introduction and cultivation of a particular 

 kind of grain or fruit into a country will tend to 

 attract some of the wild animals from the surround- 

 ing forest to the cultivated ground, and to increase 

 their numbers by the food so readily obtained." 



* Pp. 77. 78- 



