It is magical to see butterflies high up in the air. It is also magical to see great quantities of butterflies in flight at once.
We have migratory butterflies here in Iowa, and sometimes they accumulate in great numbers. They include red admirals, painted ladies, monarchs, and others. American snouts get up here, too, but usually only in small numbers. In Texas they often form great swarms.
Charles Darwin witnessed a great flock of butterflies, off the coast of Brazil, and he wrote about it. His book about the Voyage of the Beagle was wildly popular, when it was first published in 1839—long before he published The Origin of the Species.
I wonder if the phenomenon he witnessed still exists, and if it does, are the numbers as high as what he saw?