This is a very attractive butterfly which, like many migratory species, appears in May/June and returns in great numbers in September and later. Having seen so many Berger's Clouded Yellows (C. alfacariensis), including many quite bright yellow ones, I am no longer 100% certain of identifying these two species accurately without a good look.

observations

a more typical crocea, a strong pink edging to both wings.

a rather dirty ground colour (altitude effect?) even though the specimen is quite fresh, and delicate slightly pink edging to both wings (I've never noticed this before - maybe it's an advantage of the close-up shot). There are no upf apical markings visible through the wing indicating male, and the hindwing margin is quite straight which also confirms male. The unh discal spot is very large and heavily ringed and silvery inside, and the second, usually vestigial, spot is large.

a male crocea taking salts.

a female. The apical yellow marks are showing through quite clearly (in the male, the black areas are solid) and the hindwing is rather rounded.

a female of the form helice. It is sometimes considered that helice makes up about 10% of the UK population of female crocea, although my experience suggest that that percentage is higher in southern France. ID is not a problem in the UK as there is nothing similar, but in France the female alfacariensis is white and looks, at least superficially, very similar. The underside is 6721.

the underside of 6719. The pastel yellow of the unf indicates crocea of the form helice, whereas the female alfacariensis is white in this area.