A small kingfisher is a very tiny bird, quite rare. Because of its small size, thin legs, and slender neck, it cannot be used for tying message scrolls for delivery. However, it does have two advantages: one, it flies with incredible speed; two, it's very intelligent, capable of remembering a small number of characters, and can even write them out after dipping its claws in tea water.
Now that Hua Yan had no birds or eagles for sending messages, she thought of the small kingfisher raised by He Tan.