Where can I find Dust Spirits?

I managed to snag 2 of these in one night at Granite Falls. It's entirely luck based as a previous game I couldn't find any. The first ones I found near the end of the river by the fishing spot (not the waterfall end), if you are facing the fishing spot look to your left near the raised ground and they're around there. The other spot was by the forest edge, if you face the entrance to the toilets then look south-west from the toilets to where the edge of the forest is they're close by there near the rocks not far from the strawberry plant there.