If you need to grab a second quetzal for breeding and you already have one, I recommend using your first quetzal to chain bola the secons one and place stone gates on its neck, body, and legs. You can then proceed to tranq it no problem. Oh, and you might want to bring some spiked walls to keep the predators out.
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.