Large aggro radius and travel in flocks, be careful!

If low lvl build a trap to lure them into using foundations, walls and ramps. They tend to prioritize wild herbivores over you so sometimes you can catch them distracted by a Trike or Stego and tranq them (make sure to kill or distract the Stego quick before it kills the birds).

If higher lvl, build flak armor and just facetank them while firing darts, they have low topor so usually 3-5 darts downs them with a primitive longneck. You could also use a tamed Rex or Spino to draw their aggro by dismounting and mounting then tranq them while they are distracted.

More Terror Bird Taming & KO Tips