360 THE EVOLUTION THEORY 



we can prove that many have already succumbed in the strugc^le 

 with man, and we anticipate the extermination of others. But the 

 reason why they are so readily exterminated obviously lies in the fact 

 that they have surrendered the advantage given to them by their bird- 

 nature, by adapting themselves to terrestrial life, and that they are 

 not able to regain it, at least not in the short time that is at their 

 disposal if they are to be saved from extermination. The best 

 example of this is the Dodo (Didus ineptua). This remarkable-look- 

 ing bird, of about the size of a swan, lived in flocks upon the island of 

 Mauritius until about the end of the seventeenth century. It had 

 small wings with short (juills which were useless for flight. As it 

 could neither escape by flight nor through the water, and could only 

 move clumsily and awkwardly upon land with its short legs and 

 heavy body, it was hopelessly doomed as soon as a stronger enemy 

 made his appearance. It fell a victim to the sailors who first landed 

 on the island and clubbed it with sticks in huge numbers. Until that 

 event it was without doubt excellently adapted to life on that fertile 

 island, for on a volcanic island in the middle of the ocean there were 

 no large enemies, and it was therefore not dependent on the power of 

 flight for safety, and could pick up abundant food from the ground. 

 But when man suddenly appeared on the scene and began to per- 

 secute it, it was not the ' senile rigidity ' of its organization that 

 prevented it from making use of its wings again ; it was the slowness 

 of variation and consequently of selection, which is common to all 

 species, which impelled it to extinction. The same fate will probably 

 overtake the Kiwi of New Zealand {A'pteryx au&iralis) in the near 

 future, for though it has so far escaped the arrows of the aborigines, 

 it is not likely in its wingless condition to be able to hold out long 

 against European guns, unless close times and preserved forests are 

 instituted for it, as they have been for our chamois. 



Even sadder from the biologist's point of view than such exter- 

 mination of individual species through the vandalism and greed of our 

 own race is the disturbance of whole societies of animals and plants 

 by man that is going on or has been accomplished on most of the 

 oceanic islands, and we must briefly notice these cases while Ave are deal- 

 ing with the decadence of species. I refer to the crowding out of the 

 usually endemic animal and plant population on such islands through 

 cultivation. The first step in this work of ' cultivation ' is always the 

 cutting down of the forests which for thousands of years have clothed 

 these islands as with a mantle of green, have regulated their rainfall, 

 secured their fertility, and allowed a medley of indigenous animals, 

 usually peculiar to the spot, to arise. We have already spoken of 



