STEP-PARENTS AMONG BIRDS. 95 
mallard duck is monogamous in the wild state, and a 
Mormon of the Mormons when domesticated. 
Very closely allied genera or families—even spe- 
cies—differ strikingly in permanent habits, as we saw 
in the last chapter. Again, they may hint their kin- 
ship in their frailties. Our crow blackbirds are mo- 
nogamous, but show some quite Lotharian tendencies ; 
the red-winged or swamp blackbird is polygamous 
usually, and the cowbirds on the border of the family 
are indifferent to any connubial ties whatever. The 
weakness of Nuttall’s oriole may have been an inherited 
tendency, since he is in the same family with all these. 
Of course, among the purely polygamous birds such 
vagaries count little, and step-parents may occur with- 
out death, as with the ostriches, for instance, where 
many females lay in the same nest. Mr. Darwin notes 
a correlation which may tend to prevail between bril- 
liancy of color and polygamy, so that any bird that is 
pretty may be liable to suspicion asa flirt—a very natu- 
ral conclusion, tending to hold beyond the feather. 
But the writer has observed in the male cardinal the 
most unselfish paternal interest, where, unmated him- 
self, he helped a pair of blackbirds feed their young. 
Of course, there is yet that other form of step- 
parents, blameless except for its stupidity, where one 
bird hatches and rears the young of another, to the 
injury and loss of its own, as seen in the parasitic 
habits of the American cowbird and European cuckoo. 
The adoption by a common hen of any bird that 
she has hatched, as a duck, is a form of step-parental 
affection common in almost any barnyard. 
