Heavy desert rainfall has been keeping large swarms of painted lady (Vanessa cardui) butterflies in California, delaying their migration. These clouds of butterflies — likely numbering in the millions — in Southern California are en route to the Pacific Northwest. But scientists say the ample rain, which allowed plants to thrive and supplying caterpillars with food, seems to have caused the painted ladies to change their usual migration schedule. The butterflies appear to be staying longer in Southern California, rather than reaching Northern California by the time they usually do.
Read more about the painted ladies in the New York Times.
Watch below to see the butterflies in action.