The ants nests have been erupting with flying ants today in the heat. I noticed it in two different places near Skircoat. At one there were two different species flying from different, adjacent nests.
Dave Sutcliffe mentions it as well on the Calderdale Birds Blog.
I seem to remember an entomologist asking for data on this phenomenon on the Radio 4 Today programme a bit back. Anyone else hear it, or noted ants flying from their nests?