68 THE MEANING OF EVOLUTION 
has been here a fit quality and has helped him in 
the race. 
Man is only slowly coming to be a city-dwelling 
animal. Although it is a voluntary process with him, 
he still usually visits the country with much enjoy- 
ment. He has not as yet learned to adapt himself 
thoroughly to the city, for somehow city life kills 
him. Families that move into the city gradually have 
a smaller number of children in each generation until 
shortly the family is wiped out. The population of 
the city must constantly be replenished from the coun- 
try. But the English sparrow is more adaptable than 
are the people. He has made himself at home in the 
heart of the biggest city. The Wall Street canyon is 
not deep enough, nor contracted enough, nor free 
enough of food to blot out the life of the English 
sparrow. At the heart of the deepest gully among 
the skyscrapers of our biggest cities we find this little 
bird hopping between the horses’ feet, darting out 
from under the wheel of the push-cart, fluttering only 
a few yards to a place of safety, to return at once to 
his scanty meal upon the pavement as soon as oppor- 
tunity offers. He is a typical city dweller and has 
learned to thrive there. Again in this matter he has 
distanced other birds to whom the city is more deadly 
than it is to people. 
Another very important element in his fitness for 
