When the weather turns chillier it is tempting to jump aboard a plane and head south. Insects like the Monarch butterfly have built-in wings and do just that. Dragonflies, too, are known to migrate. Here is your guide to watching them.
Monarchs
The Monarch, Danaus plexippus, is a large black and orange butterfly found in North America, northern South America, Hawaii, Spain, Portugal, Australia and New Zealand. Only North American populations are migratory, flying south to locations in California and Mexico where they overwinter in the millions.
The species is not endangered, but the migration is considered a “threatened phenomenon” due to elimination of the insect’s host plants, milkweeds, due to agricultural practices and urban development.
The overwintering site in Mexico is endangered by illegal logging and irresponsible ecotourism enterprises that disturb the roosting butterflies, causing them to burn the fats they need to start their return journey in spring.
Watching the Monarch Migration
The adult butterflies are built for long-distance flight. Their broad wings allow them to glide more than fly, conserving energy over so many miles. They also fly at surprisingly high elevations. Go to the tallest building in your city this fall and you may very well see Monarchs streaming overhead. The best time to find them roosting is in the early evening when they descend into groves of trees and thick vegetation, and in the early morning before they warm up and depart.
Dragonflies
It has recently become apparent to scientists that certain dragonfly species also migrate in large numbers, especially along coastlines. These events can be confused with normal “feeding swarms” when dozens if not hundreds of dragonflies gather in a small area, flying erratically as they feed on midges and other abundant small insects.
Dragonflies in migration display a distinct north-to-south flight path.
Report Your Observations For Science
It is important to record your observations of insect migrations so we can have a collectively better understanding of them. Monarch Watch and Journey North are two organizations keeping an eye on Monarchs. The Xerces Society is part of the Migratory Dragonfly Partnership that is monitoring dragonfly migration events. All of these websites offer fascinating information about these insects and lead you to ways you can report your own sightings. Have fun making discoveries!