Complex sentence: Although many people believe this owl has exceptional night vision, its retina is no more sensitive than a human's and its asymmetrically placed ears are key to its hunting by giving it excellent directional hearing.
Split into simpler sentences: Although many people believe this owl has exceptional night vision, its retina is no more sensitive than a human's. Rather, it is its asymmetrically placed ears that are key to its hunting because they give the tawny owl excellent directional hearing.