The most obvious explanation is that swarms are groups of migrating dragonflies.
From the post-gazette.com
Some are conventional training companies migrating online, others are start-ups.
From the economist.com
Since then the Kontact components have been gradually migrating towards Akonadi.
From the en.wikipedia.org
Migrating from Windows 9x to XP can be an issue for users dependent upon MS-DOS.
From the en.wikipedia.org
It's helping researchers see how the dengue virus is migrating through the city.
From the npr.org
Animals in the Arctic are accustomed to migrating at a certain time of the year.
From the stltoday.com
In fall and spring, the platform is an excellent place to view migrating whales.
From the sacbee.com
But animals migrating from one population to the other can confound the results.
From the newscientist.com
The proportion of migrating males increases as they travel south through Europe.
From the en.wikipedia.org
More examples
Move from one country or region to another and settle there; "Many Germans migrated to South America in the mid-19th century"; "This tribe transmigrated many times over the centuries"
Move periodically or seasonally; "birds migrate in the Winter"; "The workers migrate to where the crops need harvesting"
(migration) the movement of persons from one country or locality to another
(migration) a group of people migrating together (especially in some given time period)
(migration) the periodic passage of groups of animals (especially birds or fishes) from one region to another for feeding or breeding
"Migrate" is a song by American singer and songwriter Mariah Carey from her eleventh studio album, E=MCu00B2 (2008). It was written and produced by Carey and Danja, with additional songwriting from The Clutch and the tracks featured artist, T-Pain...
(Migration (Agriculture)) Seasonal human migration is very common in agricultural cycles. It includes migrations such as moving sheep or cattle to higher elevations during summer to escape heat and find more forage. ...
(Migration (album)) Migration is the third studio album by The Amboy Dukes. It was released in 1969 on Mainstream Records (stereo S/6118). On this album, Rusty Day replaced John Drake on vocals. The song "I'm Not A Juvenile Delinquent" is a cover of the 1956 song by Frankie Lymon and The Teenagers.
(Migration (birds)) Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. ...