So... I figured out the exact spots for the spawns 👍 The primary spot is just behind the red obelisk on the thin little strip of land near the southern island. (I almost always see one spawn there) I also find them frequently spawning around the “back spike” of the red obelisk. You will almost always find a quetz around these two places. (At least on mobile) If you want a high level, just kill the one that spawns at these two places and a new one will always respawn back at those two places. This technique worked for me.
They spawn near green ob on island. On ragnarok they spawn on the outskirts of Viking bay, as well as over the plains outside of the dragon trench. On valguero they spawn pretty much everywhere you can find 2 or more recessed in one spot, or wherever Gigas spawn.
If you already have a quetzal and have a trap set up on it then I recommend looking around the lake in the middle of the redwoods, I usually find them there or in the area and you also could have a chance at an argy so win/win
I’m a lvl 84 and I’ve only seen these guys about 7 times. I was on my Argy, higher than the tallest redwood tree and I seen them. Yes they like to fly high and they have been watching you tame that lvl 45 dilo.