+18 = 21 

ㄓㄨㄢˇzhuǎn

  1. 北周·庾信〉:新年楊花滿。」·沈佺期人日大明應制。」

to sing (of birds or insects)​, to warble, to chirp, to twitter
chanter (oiseaux)​, gazouiller
singen, zirpen, trällern, trillern, zwitschern, schnattern (V)​