Painted Lady butterflies are flitting about fields, gardens, roadsides and meadows throughout eastern North America and beyond. Like Monarch butterflies, with which they are sometimes confused, Painted Ladies are now migrating southward.
Each fall, they vacate Canada and most of the U.S. and during winter are active only in parts of the extreme southern U.S. and Mexico. When spring arrives, they push northward to breed, sometimes arriving in the Northeast in large numbers. But they’re not as predictable as Monarchs.
This year there was a very early and large arrival of Painted Ladies in April and early May, and they were able to have two generations instead of one, creating a huge population that is now moving southward throughout the eastern half of North America. But about a week ago, a strong southern weather flow in the Northeast brought the migration to a lull.
“The butterflies we see are those that are nectaring on flowers for fuel. The Painted Lady butterflies that are actually migrating are likely out of our view several thousand feet in the air,” said Max Larrivée, an entomologist at the Montréal Insectarium and founder of e-Butterfly.org.
But, where exactly are they going? With a massive effort by volunteer citizen scientists, we can begin to piece together this migratory puzzle with butterfly checklisting.
When eButterfly users submit complete checklists of butterflies and their effort expended to find them, it allows us to do a variety of interesting analyses. We can show where a species is found and where it hasn’t been reported. We can calculate the chances that a species will be found at a given time of year in certain locations. And most importantly, we can develop species distribution models that show these migrations across the continent using Spatio-Temporal Exploratory Models (STEM) that have been specifically developed for checklist data by statisticians and researchers at eBird.
Visit eButterfly.org and add all of your butterfly checklists, with and without Painted Lady observations, everyday this fall and help us unravel the mysteries to their migrations across North America.