Most people know about monarch butterfly migration, but there are actually other insects in the US that migrate. That includes 16 species of American dragonflies!
Some researchers actually attached tiny radio transmitters to some Green Darners and followed their migration. The average distance migrated was 58 km (about 36 miles), but some dragonflies traveled twice that distance.
A paper from 1998 described mass autumn migrations of dragonflies (Odonata) in Illinois, New Jersey, and Florida. The description of the Chicago migration event is delightful–one of the authors was working in his office at the Field Museum and noticed a giant swarm of dragonflies passing by:
“The flux of migrants was estimated from the museum rooftop by counting dragonflies as they passed through a 400-M2 (40 m long X 10 m deep) vertical window to the E. …At the point where migrants were passing the museum, the dragonfly stream was estimated to be 850 m wide. Assuming that passage rates were constant throughout the 5-h period during which the migration was in progress, ca. 1.2 million dragonflies were estimated to have been involved in the flight.”
The Migratory Dragonfly Partnership (MDP) has started a citizen science project to investigate the movements of two migratory dragonflies: the Common Green Darner (Anax junius) and Black Saddlebags (Tramea lacerata).
You agree to visit the same wetland or pond site on a regular basis, and then report the arrival of migrant dragonflies moving south in the fall or north in the spring. They also would like to know when the first resident adults of these species emerge in the spring. Sign up at Dragonfly Pond Watch
More info about migratory dragonflies: