If you're walking in the woods, you're probably going to get more annoyed by a loud, screeching bird call than a soft, complex birdsong. But dark-eyed juncos are just the opposite. These birds will find and fight their soft-singing peers.
Dark-eyed junco birds are one of many species that practices monogamy...to a point. While a male and female are pair-bonded - the junco equivalent of marriage - both partners will take on additional partners in the name of better genetics.