To solo KO this dino, jump off your bird with grapple equipped, grapple onto your bird then whistle it to attack the quetz, when you are near, whistle 'stop all'. Switch to tranq darts and shoot, rinse and repeat... gl!
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.