I have mixed felling a about this feathered jerk. I had knocked out a Rex and went meat collecting. When I came back, a terror bird was killing it. I shot arrows at the bird, but the bird killed the Rex. I slightly like it because you can glide to safety with it
Terror Birds are very fast animals so out running them will be hard so more movement speed will be needed for this and combat on foot will be relatively easy considering they share almost the same stats as a raptor, so low health
One thing to know is that they can be glitchy.One way you could exploit is to stand in its hitbox and pike/sword it.If you have good stam and speed then simply run at enemies and make him agro onto that.If niether and you just started out you could try to out swim it.One other thig i suggest is that u bola them.Also if you have a house with a normal door run in open the door and pike it (it's pretty much an exploit) but it can't damage you.Last but not least i say you should hit it through the wall if you have anything other then a pike.