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 



