Possible Clues:

• Fish-eater thus going over quarry
• I grab fish, thus lifting my catch?
• Sea bird
• Marine bird of prey
• Bird and the big creature it's out to catch?
• This predator's victims are enormous!
• So the raptor turns on its victim
• Large bird that preys on fish in inland waters
• Taloned predator
• Predator thus reversed — then the opposite?