I received a fair number of reports of dragonfly swarms, based on the last blog post, and other stuff that I've written about this phenomenon. The map above shows locations of the last few days' reports, and nearly all observers indicated swarms of "dozens", but more often "hundreds" or "thousands". From the evidence at hand, the vast majority of dragonflies involved were Common Green Darners, Anax junius. Most reports were made in the waning hours of the day - often near twilight.
These mapped locales represent but a fraction of the reports that were made. I saw numerous mentions of dragonfly swarms on Facebook and elsewhere. And two respondents to me live in Illinois, and saw massive swarms there. One can only imagine the untold millions of these big dragonflies that moved through the Midwest in advance of the current cold front. It would be fascinating to know with certainty where these animals are headed. Possibly the Rio Grande Valley of south Texas? Mexico? Deeper into Central America? My hunch is that they disperse on a broad front across the Gulf States and then south into Mexico and perhaps beyond. Hopefully, someday this migratory dragonfly mystery will be thoroughly unraveled.