A 1 1/2 inch butterfly that is native to Europe and introduced to North America in the 1860s where it is a pest species to agriculture.
"The species can be found in any open area with diverse plant association. It can be seen usually in towns, but also in natural habitats, mostly in valley bottoms. Although an affinity towards open areas is shown, the small white is found to have entered even small forest clearings in recent years."
This little one was found enjoying nectar at St. Fagan's Outdoor history Park near Cardiff, Wales.