In the ancient poem "The Bird's Nest Over the South Branch", what does the bird's nest symbolize?

Nineteen ancient poems of Han Dynasty "Traveling, walking, walking again": Walking, walking, walking again, I will be separated from you. They are more than ten thousand miles apart, and each is at the end of the world. The road is long and difficult, but we know the meeting will be safe. Hu Ma follows the north wind and crosses the southern branch of the bird's nest. The sun is far away from each other, and the sun has faded away; the floating clouds cover the day, and the wanderer does not care about the opposite. Missing you makes you grow old, and the years are suddenly too late. Don’t give up and don’t return to the road, but work hard to get more food. Huma relies on the north wind, and the bird's nest is on the south branch. The bird's nest means that a bird from the south always builds its nest on the south branch of the tree, which is a metaphor for a traveler who misses his hometown. The Yue bird also symbolizes the bird coming from the south. The ancients had different interpretations of the two sentences "Huma relies on the north wind and crosses the bird's nest to the south branches". Li Shan's "Annotations to Selected Works" quoted "Han Shi Wai Zhuan" and said: "The poem says, 'The horses follow the north wind, and the birds fly to their old nests.' They all mean not forgetting the origin." But "not forgetting the origin" can be derived from two aspects. From a perspective: From the perspective of a traveler, it is of course a positive description of his homesickness; from the perspective of a stayer, it means that Hu Ma is still attached to the north wind of his hometown, and Yue Bird still chooses Looking at Nanzhi in your hometown in the distance, as a wanderer, how can you forget your hometown and your relatives in your hometown? This is a metaphor from the opposite side. The second theory is that it comes from the "Wu Yue Chun Qiu" "Hu Ma stands in the north wind, Yue Yan looks at the sea and the sun shines". This means seeking after like. That is to say, "the clouds follow the dragon, the wind follows the tiger", everything has its own attachment to each other and cannot bear to leave; and you and I are originally a couple who love each other, how come we can be separated for so long and cannot be reunited? How about coming together? There is another saying, which is what Sui Shusen quoted Ji Yun as saying, "This means that one south and one north refer to each other as 'each at the end of the sky', so that they are far apart from each other." This statement puts aside the origin and meaning. Literally, Huma and Yuediao are in the south and north, which intuitively gives readers a sense of isolation between the north and the south.