White-eye birds are seen at a garden near Xuanwu Lake in Nanjing, capital of east China's Jiangsu Province, Feb. 19, 2021. [Photo/Xinhua]

A white-eye bird is seen at a garden near Xuanwu Lake in Nanjing, capital of east China's Jiangsu Province, Feb. 19, 2021. [Photo/Xinhua]

A white-eye bird is seen at a garden near Xuanwu Lake in Nanjing, capital of east China's Jiangsu Province, Feb. 19, 2021. [Photo/Xinhua]

White-eye birds are seen at a garden near Xuanwu Lake in Nanjing, capital of east China's Jiangsu Province, Feb. 19, 2021. [Photo/Xinhua]

A white-eye bird is seen at a garden near Xuanwu Lake in Nanjing, capital of east China's Jiangsu Province, Feb. 19, 2021. [Photo/Xinhua]

A white-eye bird is seen at a garden near Xuanwu Lake in Nanjing, capital of east China's Jiangsu Province, Feb. 19, 2021. [Photo/Xinhua]

A white-eye bird is seen at a garden near Xuanwu Lake in Nanjing, capital of east China's Jiangsu Province, Feb. 19, 2021. [Photo/Xinhua]

A white-eye bird is seen at a garden near Xuanwu Lake in Nanjing, capital of east China's Jiangsu Province, Feb. 19, 2021. [Photo/Xinhua]

A white-eye bird is seen at a garden near Xuanwu Lake in Nanjing, capital of east China's Jiangsu Province, Feb. 19, 2021. [Photo/Xinhua]

A white-eye bird is seen at a garden near Xuanwu Lake in Nanjing, capital of east China's Jiangsu Province, Feb. 19, 2021. [Photo/Xinhua]

A white-eye bird is seen at a garden near Xuanwu Lake in Nanjing, capital of east China's Jiangsu Province, Feb. 19, 2021. [Photo/Xinhua]

People take photos at a garden near Xuanwu Lake in Nanjing, capital of east China's Jiangsu Province, Feb. 19, 2021. [Photo/Xinhua]

A white-eye bird is seen at a garden near Xuanwu Lake in Nanjing, capital of east China's Jiangsu Province, Feb. 19, 2021. [Photo/Xinhua]