Which bird represents the south in the Four Symbols?

The bird that represents the south in the Four Symbols is the Vermilion Bird.

Known as Zhuque in Chinese, the Vermilion Bird is the southern guardian of the Chinese constellations. It represents the south, the Fire phase of wuxing, the summer season, midday, and the color red or vermilion. Its celestial identity makes it more specific than the general idea of a phoenix-like bird.

The Vermilion Bird is often described as a red bird resembling a pheasant, with plumage associated with flame. It is frequently confused with the fenghuang, the Chinese phoenix, because both are elegant, colorful legendary birds. They are not the same: the Vermilion Bird is a directional spirit of the constellations, while the fenghuang is a broader auspicious bird associated with virtue and rulership.

Its domain contains seven lunar mansions, including Well, Ghost, Willow, and Star. The other Four Symbols are the Azure Dragon of the east, White Tiger of the west, and Black Tortoise of the north. In Japan, the same figure is known as Suzaku; in Korea, it is called Jujak.