What season is Du Fu's "Huayang falls to the ground, Wen Daolong crosses five streams"?

Huayang fell to the ground and cried ",which was the scene of Li Bai's" hearing that Wang Changling was moving to the left "in late spring.

Two common images of spring are described here: Huayang is catkin, and catkins are flying, which not only points out the characteristics of the season, but also renders the bleak atmosphere; Zigui is a cuckoo, and it is said that it was formed by blood after the death of Du Yu, the Emperor of Shu. The cuckoo's tears of blood express a sad mood.

Wang Changling moved to the left, was demoted to the dragon label, and was in a desolate place. The poet expressed his sympathy for his friend's misfortune with the two images of "Huayang" and "Devil", and at the same time combined with his own ambition, he realized his inner sadness.