Which solar term swallows return?

Explain the solar terms of Millennium and autumnal equinox from-twenty-four solar terms in Song Dynasty.

The plum blossoms in beginning of spring are particularly gorgeous, the rain-red apricots are in full bloom, the lulin thunders, the butterflies in the vernal equinox dance among the flowers, the kites in Tomb-Sweeping Day are broken, and Grain Rain is connected with tender tea and jade.

Mulberry fruits are like cherries in the long summer, silkworms are cultivated in the small man, jade seedlings grow in front of the courtyard, rice and flowers are like white practice in the summer solstice, Xia Feng urges early beans to ripen, and Chi Pan enjoys red lotus in the summer.

Qiu Chan makes people sleep, sunflower smiles in summer, and the Millennium returns to the wild goose. In the autumnal equinox, osmanthus flowers are fragrant all over the garden, cold dew vegetables are green, and the first frost reeds are floating all over the sky.

Beginning of winter reported good news and offered three blessings, with light snow and goose feathers flying all over the sky, heavy snow and cold plums rushing against the wind, till the day is full of snow, the slight cold is homesick, and the great cold is reunited at the end of the year.

Literal translation:

One year, the Millennium solar term came, the swallows returned, and the geese came again; In the autumn equinox solar terms, osmanthus is ripe and the garden is full of fragrance.