This video from France says about itself:
The Large Tortoiseshell (Nymphalis polychloros)
7 November 2014
The Large Tortoiseshell flies from June to July in one generation, rests during summer, rarely appears in September or October. The butterfly hibernates hidden away from the cold in woodpiles, sometimes several individuals together. For several successive years 2 to 4 butterflies have been found in the same shelter in the woodpile shown in the film.
This is one of the first butterflies flying on sunny days in February or March. In 2007 and 2008 it was abundant in the Var, since it is more rare.
The sexes are similar. The males patrol their large territory. In the spring 2013, a court-flight has been observed; the male flew in a slow and graceful way around the female. They disappeared together in a swift flight out of sight. The female chooses different trees for egg laying: Elm, Willow, Poplar, the Hackberry and various fruit trees. The caterpillars live in communities on the foliage of the host plant.
Translated from Nature Today in the Netherlands:
10 MAY 2018 – Large tortoiseshell butterflies had disappeared from our country, but they seem to come back. This spring, large tortoiseshell butterflies have been seen at more than thirty locations. They probably have overwintered there. The wait is until successful reproduction is established, for example because caterpillars are found.