So uth duna is pretty interesting when it comes to moving around the map, and i've noticed it mostly comes down to watching the weather patterns. You'll mainly spot this big guy in the scarlet forest when the downpour kicks in, which actually makes a lot of sense since it needs all that water to move around properly.

I've found that tracking its movements isn't too complicated once you understand what makes it tick. It's got this cool water veil thing going on, and it pretty much sticks to flooded areas where it can use that to its advantage. Something neat i learned is that it really goes where the food is, especially during those downpour phases when all the aquatic creatures are out and about.

One thing to keep in mind though, is that uth duna's basically the boss of the scarlet forest, and it doesn't play nice with other monsters in its territory. I've seen it chase off rathalos more than a few times, which is pretty wild to watch. While it technically can pop up in areas between biomes when they get flooded, don't expect to see it wandering into the desert or anything - it's really picky about staying where there's plenty of moisture. Makes hunting it a bit more predictable, which is definitely helpful when you're trying to track it down!