At least, it is rare in The Netherlands. Presenting: the white admiral (Limenitis camilla), kleine ijsvogelvlinder in Dutch.
These butterflies feed mostly on blackberry flowers, and lay eggs exclusively on honeysuckle.
This is the first photo I ever managed to get of one, taken yesterday:
Olympus Stylus 1s, 300mm, ISO200, f5.6, 1/250s
It is in the same family as the equally rare purple emperor (Apatura iris), grote weerschijnvlinder in Dutch:
Olympus XZ-1, 112mm, ISO100, f8, 1/125s
The two are often confused, also because the blue sheen of the purple emperor only shows up under certain angles; from other angles, it looks brown.
Another identification pitfall: the summer form of the map (Araschnia levana), landkaartje in Dutch, also looks similar to the white admiral.
Thanks for watching!