You can find these little guys in basically any beach. Tamed one and saddled it and it is quite useful! You can also fish while on it in the water which is really useful if you dont have a raft. However the speed is quite low and you cannot hold creatures with it.
Currently it's untamable in primitive plus due to the raw fish meat being replaced with fresh fish filet my friends and I tried prime meat and prime fish meat but no luck hopefully this will be patched in a upcoming update
One of the best birds out there lands on water collects a lot of polymer I got like 500 polymer in one trip to the snow kills fish easy and I tamed a high level one mines at 250 right now so its strong I kill alpha carnos and Rex's with it so its not a weak bird unless u tame low level and it can carry a lot and its pretty fast 2 all in all the landing in water helps so much
Build a small pen. Place a bunch of AC and tame around 30 penguins and put them wander so they lay eggs. Then trap pelagornis in room so everytime the penguins hatch the pelagornis will gather the body's polymer
When taming these, if you find one out in the water, punch it then follow it inland it will land there and you can bola it and KO it. On rare occasions they may land on your boat making for an easy tame. Most common around Craggs Island. They make super cute noises aswell. Remember they only eat fish meat and they eat a lot of it so stock up b4 hand. If taming on PvE don't expect to find fish in small rivers. The worlds are far to established and fish are very scarce depending on the area. Not a lot of narcos are needed though as their torpor depletes very slowly