62 THE MEANING OF EVOLUTION 
stances should be their lot. But there is room in this 
environment for a definite number of bluebirds. When 
this number was suddenly reduced the chances to make 
a bluebird’s living were so wondrously multiplied that 
young bluebirds had such an opportunity in life as 
their fellows had not had for many long years. Ac- 
cordingly they thrived as never before, and, of their 
progeny, a larger proportion lived to the following 
year. It was only a few years before the number of 
bluebirds had risen. Now we probably have as many 
as we have had for a long time past. I cite this 
simply to show that a region can support a certain 
number of animals of any one particular kind, and 
that the animal is likely to multiply, if given a fair 
chance, until it has reached such proportions. Now to 
my story of the rapid development of a newcomer. 
In the year 1850 a resident of Brooklyn came home 
from a trip to Europe. He was a lover of birds, and 
while in Europe had been particularly attracted, no one 
now knows quite why, to the common House Sparrow, 
as it should be called. It is no more abundant in 
England than in many parts of the continent of Eu- 
rope. A name that has been used for a long time is 
very hard to cast aside, and we shall probably con- 
tinue to mistakenly call him the English Sparrow to 
the end. Our Brooklyn traveler brought home with 
him from Europe eight of these interesting little birds 
