It would seem odd that a male bird, since it is in their habit to build a nest, would instead seek to live in one built by another male. Might be a genetic defect. Happily for that species, that defect will be removed from the genetic pool in each instance in which it appears.
The bald eagle isn't extinct yet - it happens very often in that particular species. Maybe that's why that nutcase that is protesting soldier's funerals with his "God hates Fags" signs is so anti-American!