Daubenton's can often be seen flying low over open bodies of water where they trawl for insects close to the surface using their feet and tail membrane. I was surprised to see such good numbers last night at Chard Reservoir - at least 25 of them in a feeding group close to shore and probably many more around the perimeter of the water. I shot the short video below on my phone just to illustrate part of the feeding group. The sound you hear is my bat detector going crazy and you may be better off watching this on YouTube to see the video enlarged.
The Soprano Pipistrelle was particularly vocal: