I'm sure there is some statistical analysis that can be done to predict whether a leaf will fall from its petiole, 20 metres to the ground, to land and become part of the photographer's image or be swiftly carried along by the stream which is fast-flowing and narrow, wide and slow in places, to flow towards the sea.
Or indeed to be thrown on to a rock and deposited there as higher water recedes.
The green moss here vibrant from recent wet weather, the same precipitation that feeds the stream and helps to bring those dried leaves to the ground.
And it's a scenic sight, reds and greens saturating this small corner of the Irish countryside.
The challenge on this morning was to keep the camera dry, but amazingly the afternoon turned to bright sunshine and all with a warm breeze.
Recently I was asked what Ireland is like in October, is it worth coming to for photography and of course my answer was indeed it is worth visiting in October.
Here are some of my favourite images from Octobers over the years, a small selection but waterfalls and woodlands make up a lot of the locations.
Donegal is Ireland's most northerly county, its peninsulae jutting out into the North Atlantic with Malin Head being the northernmost point on the island.
And it is a scenic part of Ireland, the coast is long with rocky sections, cliffs, sandy beaches and with more than a few lighthouses it lives up to its reputation as a rugged place.