Grapple an argentavis and go find a low level quetzal (faster knock out). Then dismount it and use your spyglass to whistle attack my target aiming the quetz. When you're close enough shoot it in the face as redo the process with the spyglass.
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.