Initially when I looked at the river all I could see on the water were circular ripples like rain drops hitting the surface. When I had a closer look I realised the circles were actually being made by what were probably 100s of Water Striders. They moved incredibly quickly across the surface of the water without being disturbed by the wavelets. They did not seem concerned about how obvious they were but nor did I see any bird, or anything else, predating on them. This was the brownest I have seen the Murrumbidgee River at Casuarina Sands.