House Wrens build dummy nests exclusively with small diameter twigs. When a male is trying to attract a mate he fills all the cavities he can find with twigs. If a female accepts one of them, he’s a lucky guy. The acquisition of a mate doesn’t mean the end of his attacks on all the other nests in his territory. He continues with this behavior in an effort to protect the food supply. I never, ever let them succeed here because that would just mean more wrens.
And, no, you can’t control nature. All you can do is offer your best protection.
Gin
Atlanta, GA