When you encounter this bird it is passive unless you take its egg. It's battle attacks are a spin attack and it does the most damage. The other one is a bite attack at it's not as effective. So when in battle do a spin attack to beat your foes.
dont send your ptera to fight another one cause they will continue to spiral upwards and fly super far in the sky, and you'll lose them. I thought I lost mine, then I found you can summon them so I got him back. He was tamed at level 150😁