STEP-PARENTS AMONG BIRDS. 93 
by the presence of another male which pried around 
the nest persistently, notwithstanding the occasional 
thrashing he got. There can be little doubt that had 
the rightful husband died the other would have been 
installed at once in his stead. 
But why these unmated birds do not find each 
other and let other folk’s spouses alone is more of a 
mystery. 
It may be that they are young and inexperienced 
in partner catching, and fail in the struggle with 
widows and widowers in the fascinating arts, just as 
others do. 
It is not at all improbable, as Mr. Darwin notes, 
that there are certain incompatibilities of temper and 
taste that occur among birds which prevent them from 
finding just the right partners among each other till 
it is too late; or they may also have been unfortunate 
in losing a partner. They may have mutually agreed 
to separate because they could not agree, for there are 
some very creditable records of mated birds disagree- 
ing about many things. 
It is to be feared that there is a less excusable 
feature in all this, and while constancy is the rule 
above polygamy, some individuals of any species may 
sigh for change, even in a summer marriage, and de- 
sert their mates for others. Nuttall notes that a Bal- 
timore oriole had quite a tendency to linger in the 
society of his neighbor’s spouse, and that his wite 
won him back again ; and there are various instances 
of connubial vagaries in both sexes. Even that beau- 
tiful constancy so long emphasized in song and senti- 
