This magnificent butterfly is generally not common, though it is widely
distributed throughout Europe, extending by migration to places where
it is not resident.
The butterflies emerge in high summer and disperse, when they can be
found pretty much anywhere, though they are most likely to be
encountered in forested regions. They then go into hibernation at sites
where the foodplant (principally Salix alba
but also other willows or poplars) is plentiful. Such sites may be used
year after year and it is easier to find this butterfly in the spring,
by looking in known hibernation sites, than in the summer. The flight
period is also longer in the spring, in my experience.
The adults take the nectar of many plants but also enjoy minerals on
the ground. Here is a video of the first Camberwell beauty pictured
above doing this, and sunning itself at the same time:
