If you look closely in the photo of the waterfall in the river at Ponte a Serraglio you will see a seagull. I watched this bird over several days and he always appeared in the same spot on a ledge in the middle of the overflow.
He is clearly standing there waiting for a fish to come hurtling through the water towards him. It must work because it is his regular place.
Our ducks seem to be disappearing slowly, but the seagulls are always on the river.