These birds are hard to tame flatout above water. They cant be tranqued in the water but if u have a quetz handy u can make a 2x2x2 box out of thatch on the quetz platform then run the peligornis threw the wall and hes trapped. Open ur door to ur box and start shooting remember that the peligornis will slode forward so build door on side or back because the peligornis will slide threw the doorframe and off the quetz if its tword the drivers exit location on the quetz.. thank you good luck :)
I didn't saw anyone saying thing but if you go near one with a boat and just stay still they actually come and land on one of the edges of the boat. After that just bola him and shoot so you can tame him safely on the boat. Bring alot of narcs because torpor does come down quite fast and it takes alot of time for him to eat.