Easy way to knock it out is to make sure the surrounding area is safe, then let it knock you off your mount and stun you for 10s. After that it stays aggro'd on you so just slap a bola on that bird/raptor (idfk) and club/tranq it.
These little guys normally see you before you spot them. But go into an area with a good horse and when they start to circle you to try and knock you....start kicking! I actually Ko'd one at random and tamed her up. Actually a beautiful baby I named Fifi, a suitable name for an ankle-biter! XD