when you knock a pteranodon out you need to stave it to the recomended amout of food.after this you want to put the food in the inventory and wait for it to tame but make sure you have spare meat in the birds inventory. this it good for if the kibble runs out you bave back up to not loose taming effecince. PS. this only happens if you are using kibble. thank you for reading i hope this helps in anyway.
When knocking pteranodons out, be sure to have a bola, it doesn't take many tranq arrows to knock it out. Once it is down, put spike walls up around it (with a little space so you can go in and out) so it doesn't lose taming efficiency or die.
To kill pretty much anything on these birds, tame a high level, then pump stam to 3k, then the remainder in melee. Barrel roll into alphas etc. But keep eye on Stam. Never regen Stan on ground, know your ledges!