I feel bad for this male bird. He is stuck encoded with a behavior that he can't break no matter how hard he tries he has to attack this interloper he sees. It could actually cost him his nest and his mate. While he is distracted by a reflection a real rival could get in there and steal what he protects. The idea that a human male could be caught in the same pattern is frighteningly realistic but the poet manages to break away from the pattern by paying attention to what he cares about and that gives me hope for the species.