I think nature photography, especially at these spots, requires a lot of patience and observing skills. Some technical photography skills would come in handy too, like knowing how to maneuver the camera settings manually, especially when you're trying to capture fast-moving objects like birds!
An intrepid spirit is certainly helpful, coupled with dedication because these spots can be unpredictable; you never know what you might encounter on any given day. But that's part of the adventure and keeps things interesting!
Having some knowledge about the behavior of the local wildlife would also enhance your photography game, so you know what to look out for or the opportune moments to capture. And of course, as you mentioned, sheer grit and perseverance will eventually pay off when you least expect it, with that one epic shot.