82 THE MEANING OF EVOLUTION 
when once she has set her mind on home-making. A 
bird-lover, some time since, reported how a pair of 
sparrows had started to build a nest upon his lawn. 
He, wishing to interfere with the process, took a small 
rifle and shot the male bird. Within twenty minutes 
the female, who had scouted round the neighborhood, 
returned with another mate and resumed her nest- 
building process. Again he interjected the tragic note 
into her life by shooting her second husband, only to 
find her start out in pursuit of a third, with whom she 
returned in the course of an hour. He felt that by 
this time he had interfered with her domestic happi- 
ness as much as he had any right to do, and suffered 
her to continue her housekeeping with her third hus- 
band without further molestation. I imagine it would 
have puzzled both birds to tell who was the father of 
the nestlings who appeared two weeks later. 
Not only do sparrows nest early, they nest often. 
I suggested to one of my students that she locate as 
early in the season as she could the nest of a pair of 
English sparrows, which was sufficiently accessible, 
and that she keep it under observation at intervals of a 
few days throughout the summer. In the fall she 
came to me with glowing eyes and gave me her re- 
port. “It is simply great,’ she said. “I never went 
to that nest a single time this summer to find it empty. 
When I first got there I found four eggs; after a 
