In the northern part of North America, most butterfliers in the fall hang up their binoculars and cameras and head into semi-hibernation. However, more than a few simply head south in November to the Lower Rio Grande Valley in Texas. I have joined them from Ontario in the past two years and have been astounded by the results.
While butterflies in most parts of the continent disappearor drastically dwindle by autumn, the number of species and individuals in southern Texas increases exponentially. Even on overcast days, you can see hundreds and even thousands of butterflies. Over about a month in the combined last two Novembers, I found 118 different species.