Nearing the end of what anecdotally appears to have been a strong summer for the monarch butterfly population in Pennsylvania and elsewhere, the butterflies are coming up on time for their fall migration to mountains in central Mexico, just as Hurricane Florence is expected to smash into the region.
But the monarchs' recent trend to make their southward flight a few weeks later in the year than in the past appears to be playing in the butterflies' favor this year, according to Victoria Pocious, a postdoctoral research in the Department of Entomology at Penn State.
Pointing to data on the Journey North website, she noted that no migration roosts - clusters of tens to thousands of butterflies that gather for the night or periods of inclement weather along their migration route - have been reported in Pennsylvania or farther south.
Migration roosts have been reported north and west of Pennsylvania.
That likely indicates the southward monarch migration has not yet reached Pennsylvania.
Journey North is a 25-year-old, web-based effort to track animal migrations across North America through citizen-science reports from more than 60,000 families, teachers, schools, nature centers, scientists and others.
But, even if the migration was in full swing when Hurricane Florence comes through Pennsylvania, the butterflies likely would weather the storm just fine.
"Even if they are soaring at a thousand feet," Pocious explained, when they fly into the changing weather patterns, "they will come down, find a tree out of the wind and form a roost" to ride out the storm.
"The butterflies are smarter than we give them credit for," she said
Any caterpillars that have not yet transformed through the chrysalis stage and into adult, winged butterflies will escape the worst of the weather by crawling down into the denser portions of the plants they are on.
Pocious noted that monarch butterflies have been observed riding out hurricanes and several weather systems many times in the past.
Monarchs in eastern North America make a southward migration flight of thousands of miles to Florida and Mexico in late summer and fall. They winter there and then in the spring make a multi-generational return to the north.
More about butterflies in Pennsylvania:
- Where are the monarch butterflies this year?
- 15 common butterflies of Pennsylvania
- ZooAmerica Regal Fritillary Conservation Program works to restore rare Pennsylvania butterfly
- Monarch butterflies set record day at Hawk Mountain Sanctuary