But when our yellow warbler, finding this strange egg of the cowbird in her nest, proceeds to bury it by putting another bottom in the nest and carrying up the sides to correspond, she shows something very much like sense and judgment, though of a clumsy kind.
"Ways of Nature"
John Burroughs
I have found a deserted phoebe's nest with one egg of the phoebe and one of the cowbird in it.
"Ways of Nature"
John Burroughs
Why does the cowbird lay its egg in another bird's nest?
"Ways of Nature"
John Burroughs