Unlike poetry, the calmer and more scientific observations recorded in travelogues and herbal compendia point out that in fact it is the cuckoo's red mouth which gave rise to the mistaken beliefs or poetic allusions about it dripping blood.
有別於詩詞，在經過觀察、較科學性的遊記或本草典籍中，總會冷靜指出，實在因為杜鵑赤口，才被借用或誤以為啼血。