For easy understanding,  I copy and paste some of the answers from comments section.

  • Someone had asked before why they were called birds, and there were several different responses to the expression of CG as pigeon. I dug the comments a bit for you and finally was able to get them out of the hole where they were hiding :D

    @sakie's comment: "It's because of their names in the drama. Sun in written Chinese character means FALCON but pronounced SUN. As for ChangGe, the GE sound is a homonym to the GE for PIGEON in chinese written character. Hence, you have GeSun - as in falcon/pigeon/birdies.
    This is also why sometimes you see comments about them making little eagles and pigeons as a couple.
    Also relates back to the fact that Leo when playing Feiliu in Nirvana in Fire was constantly capturing the messenger pigeons. So Leo always gets the pigeon or ChangGE lol"

    @Dragnelia's comment: "They use the double meaning of their names to name the cp.
    Sun has another meaning- Eagle/Falcon
    Ge in Changge = Pigeon/Dove
    So the cp name "GeSun"= Bird's egg, apparently us, the shippers. So we address them as "Mom" and "Dad"

    @Fairydustpuppy's comment: "A'Sun is from the Eagle Division of Ashile n his clothing embroidery patterns have eagles on them ChangGe has doves pattern on her clothing. Hence they are known as Eagle and Doves. Both birds lay eggs and is bird species...so their future children or fans are called Bird Egg."

    and another thing.. about speaking of their CP names, 3088
    @royals's comment:
    "3088 is another CP name for Reba & Leo. Lěi (磊) means three stones, so Lei= 3 Stones(Sanshi/三石)= 30.
    Alices call Reba Baba, which sounds similar to 88 in Chinese."

    (I found this there too so I wanted to add it because if necessary I don't think we can find it again from below XD)

  • WK1  37 minutes ago

    Thanks so much Biri Biri, for digging up those past explanations for the use of pigeon to symboilise Changge. Yes, native Chinese would make use of the sound of her name to think of a bird to match AS's eagle.

    The 'ge' in her 'Changge' sounds very much like how pigeon will be pronounced in Mandarin.

    Not being native a Chinese speaker, I just googled to find how why they used pigeon

  • WK1  26 minutes ago

    @biri_biri But apart from sound, I do feel that the use of those bird species were highly appropriate.

    Eagles are used in hunting. They are fierce birds, often attacking smaller birds. AS said, in the grasslands, big fish eat smaller ones. So, eagles will be right for him, he needed to be fierce and strong, in order to survive.

    Pigeons are gentler birds. That Changge should have dove patterns on her clothing (as noted by Fairydustpuppy) is highly appropriate. It would convey femininity. It symbolised Changge's survival strategy as well, in the grasslands.

    You find pigeons everywhere around the world. Why so? They adapt. Whatever environment they are placed in, they would adapt and survive. That is the Changge we saw in TLB. After that scene, when she was scolded by AS (for refusing to eat and drink), she decided to adapt and survive

  • biri_biri  7 minutes ago

    @WK1 Yes, these two analogies seem like a fair enough match for them. and this seems like a deliberate nomenclature. Especially Sun's. I think his division got its name from its Tegin. Each division leader is compatible or associated with the name of the division. Maybe CG's name was chosen this way by the manga writer, perhaps because she will have this type of journey and character, but I also know that the main general meaning of CG's name is the name of the series. Long ballad... They play a lot with words and mean a lot of things. Therefore, it can be difficult to distinguish which is a coincidence and which is intentional :D

  • MyShootingStar  7 hours ago

    tell me about it. I walked out to the living to seeing my sister watching a disney movie and it just so happened to be a scene where there was an eagle flying. My mind instantly thinks of our Ashile Sun LOL!

    • WK1  6 hours ago

      The eagles part, I can explain. AS leads the Eagles division. He was last seen holding what is very likely an eagle.

      Pigeon, I can only make a guess. They are often used as a symbol of peace. And also to represent strength, determination, adaptation in order to survive, and fertility. Mabye, in Changge, they see all of these and decided to use pigeont represent her?

      It is like, if AS were to be a bird, which bird would you think of? Eagle. And for Changge? Pigeon

Thank you for putting some of the comments explaining this in a discussion and thanks to everyone whose comments were here

Ooo.. This is a smart method :) No matter how high we pulled these comments, the rope would slip out of our hands and they would all disappear again in our deep well. XD It makes sense to collect valuable analysis in this way. Perhaps those related to the episode or certain crucial scenes or areas can also be collected. Everyone has elaborated a lot of things in the comment section. It's a waste they just disappeared.