Of you want to knock out a quetzal (solo).
Its easy to use a grappling hook.
You take 2 crosbows with you.
Crosbow 1 you load with THE grappling hook.
Crosbow 2 you load with tranq arrows.
If you see the quetzal you shoot it with the grappling hook (i recommand you to take more grappling hooks with you of you mis) if you hit the quetzal and your grappling hook is stuck on it you get crosbow 2 out and you shoot it with tranq arrows.
To make sure you land save take a parachute with you if the quetzal is down you switch to your parachute and land safe.
The fun way is to jump off and grapple to your argie and whistle it to attack and since argies are slow it won’t catch up in time so tranq till it goes out also bring parachutes and consider liking so more people will know
If you drop a quetzal due to knockout, and it lands next to a giga...just know, the quetzal belong to the giga. Now you get to watch your would be quetzal get eaten by a giga. Now you can go home and cry.