Although these are real illustrations, they were only meant as models for later people to imitate, unlike today's illustrations to which are added inscriptions introducing details of a bird's ecology, habits and appearance.
只不過它是道地的圖鑑，只有鳥類圖像作為後人的描摹對象，不似今天的鳥類圖鑑，已經加上文字，介紹鳥兒的基本生態、習性與外貌。