State the significance of animals the author has portrayed through the story 'Old man at the bridge'

There is one symbol of hope in the story. At the beginning of the narrator’s conversation with the old man, the birds the old man was looking after were referred to as “pigeons,” but by the end of the story, they become “doves,” symbols of peace in wartime. The narrator makes this switch as he asks, “Did you leave the dove cage unlocked?” It is unclear whether this is a slip of the tongue, because the narrator is clearly distracted by the impending arrival of the enemy, or if Hemingway is attempting to give the image of the birds flying away an even more positive tint by referring to them as symbols of peace.