What is the image of egret in ancient poetry?

Under the egret, the curtain is long in Cui Yun. -"Millennium Banquet" Tang

Even the Sha Fei Egret, the mysterious ape howling in the lonely island. -"March Qushui Banquet is Noble" Lutang

Zhu Zhu is green for fishing, and the villages are full of egrets. -"Quiet Village in Early Summer" Lu Tang

The water burst, the heron was frightened, and the sand raised gulls. -Lu Tang's "Night Crossing Weiqiao Xiujinghua"

Egrets are also white and impure, but their colors are clean and their hearts are evil. -"The Dove" Li Bai Tang

Egrets in the mountains, white apes in the streams. -"Seventeen Songs of Qiupu" Li Bai Tang

White as an egret and clear as a cicada. -"Give Xuancheng Yuwen Taishou, Give Cui Shiyu" Li Baitang

Egrets walk and fly away, like snow spots on green hills and white clouds. -"Jing Xi Dong Ting sends Zheng Shaofu praise" Li Baitang