Hop on a tapejara front passenger seat get it to attack the quetz and tranq it try and use tranq darts instead of arrows when the tapejara gets to point blank range set it to passive and continue tranqing it will flee towards the redwoods and black sands area so have about 15 wooden spike walls and or a cryopodded decent carnivore ( thyla rex spino allosaurs etc )
Just give it some prime meat or it’s kibble have some narcotics just in case and you just need to wait and by god kill all the carnivores nearby and watch out or your taming effectiveness is ruined
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.
If your on crystal isle and your soloing it here's a good trick I used, first tame yourself a moth get a couple of parachutes and grappling hooks and your preferred amo with weapon, once you found one you like fly next to the quetzel and hop off the moth and grabbling hook it (dont forget parachute incase) and whistle it to attack quetzel the moth doesnt do damage but instead will slow it down for it bit while you shoot at it from below. This helped me tame it without having to whistle passive, attack target repeatedly.
If you manage to knock a quetzal out, try starve taming. If you never tried starve taming it’s just leaving a Dino’s hunger go to half way or lower and then you start feeding. I’ve done this many times and it’s very useful taming trick.