3 ways to tame them:
1. Make a stone trap (foundstion, doorframe, ramp, etc.). Get a bird, fly the bird, drag a dodo or a person around and make them bait. Without killing anyone the terror bird will be chasing you while you're flying in the air. Lure it into trap.
2. If you don't have a bird, you can solo it or do it with a friend. Find a terror bird. Start running to the trap. (Probably will die so put a bed in trap and respawn then repeat till bird gets trapped).
3. Bola it, shoot fast, bola it again before it tries attacking you or running away, shoot at it again.
TAKES AWHILE FOR THEM TO GO UNCONCIOUS. I once made the mistake and kept shooting as it took about 20 minutes for it to go unconcious it died from me shooting it too much.
YOU WILL NEED LOTS NARCOTICS!!!!