Common on herby island for a nice uninterrupted tame. Bola and max 3 tranqs of any kind. You will need narcotics, but not a crazy ton.

They collect large amounts of organic polymer from baby penguins

Bola it, then just trank it :)

When leveling up your pelagornis, head to the water. Tilt the head down and start killing fish. The pelagornis harvests the meat as it kills them, and does multiplies damage to fish.