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😁
These things are vicious when you steal their eggs. One time, I did so, and I just see this oversized death seagull flying at me and it pecked at me until I succumbed to my wounds. If you have the proper equipment these things are fairly easy to kill.