The meaning behind songbirds' springtime calls FacebookTwitterEmail 1of5 A Carolina wren's song is loud enough to be heard by his female across the street.Kathy Adams Clark / Kathy Adams Clark/KAC ProductionsShow MoreShow Less 2of5 An male eastern bluebird sings from the top of his nest box. His song assures his female that he has staked out territory with a plentiful food supply for her chicks.Kathy Adams Clark / Kathy Adams Clark/KAC ProductionsShow MoreShow Less 3of5 4of5 Northern cardinals form lifelong pairs. His song reassures his female that they've laid claim to a nesting site and inviting her to begin breeding.Kathy Adams Clark / KAC ProductionsShow MoreShow Less