If you are taking a terror bird there are 3 ways to do it depending if you are solo or with friends.Method number one is to pick it up with a argy or quetz and have a friend tranq it or simply just pick it up and put it in a taming pen.If you have lots of health and are feeling risky you can try to kite it around and tame it that way. Be warned terror birds lose torpor very quickly so be prepared with lots of narcotics or narcoberrys

These guys turn into bigger dodos after you get to lvl 20 there easy to kill and tame.

Am I supposed to be scared? These guys won't stand a chance against me if they get me raging and by the looks of them I already am raging I killed 1000s of Dodds and you little birds are next !

Pick him up with an Argy and fly far away from his buddies so you can safely tame him.