How dark did it get at the solar eclipse of 20 March 2015? Not very dark. Here is the effect on bulrush stems reflected in a pond.
A few years ago, the Living Field and The Farm dug out and replanted an old mill pond at Balruddery. A few bulrush sets were planted on an island, where they took and thrived.
A few years later, the bulrush witnessed the solar eclipse on 20 March 2015. Their last year’s stems changed their reflection in the water as the light dimmed. Images above (top down) at 9.27, 9.29, 9.34, 9.35, 9.44, 9.51 (local time). A small effect at the earth’s surface. The birds still went about their business.