Common Checkered Skipper (Pyrgus communis) nectaring on small yellow Compositae
Gray Hairstreak (probably) (Strymon melinus) nectaring on Prairie Bluets
Lyside Sulphur (Kricogonia lyside) also nectaring on Prairie Bluets
All three of these small butterflies were on low growth above a "seep" slope leading down to a long skinny pool fed by seepage from a rocky area upslope. Here's a view of the habitat.
The water barely shows, with emergent vegetation quickly filling in. There's a terrace berm to the left, beyond the water, running parallel to a line of brush (on the rocky hump out of sight to the right) with the water accumulating in a long skinny line at the base of the berm. The berm is the result of an attempt to reduce erosion when this was a plowed field many decades ago. The roof in the distance (showing against the line of dark trees) is a rain barn, collecting rainwater into tanks for wildlife.