Any mail delivery ducks?

There are ducks that send letters. In China, there is a traditional folk custom called "sending ducks". This custom usually occurs in rural areas, and when people need to send a message to a distant friend or relative, they will adopt some special ways, such as tying a small paper duck with a note or letter, and then send the message through the duck. This way is mainly an interesting and unique way that allows the message to be delivered in a special form. That is why there are letter ducks.