Male, Switzerland, May 2006

Female Switzerland, long ago

Both these pictures were taken in the Swiss Alps. The first is almost certainly a pale clouded yellow, as opposed to Berger's pale clouded yellow, which resembles it closely. The second I am not so sure about, although I now incline to the view that it is also a pale clouded yellow. It is only possible to be reasonably certain with a view of the upperside, and especially the male upperside, on the hindwing of which there are prominent orange spots in Berger's (the same spots are less strikingly bright in pale clouded).

There is good precedent for this confusion. In South's British Butterflies, which came out at the turn of the 19th/20th centuries, all the picture of 'pale clouded yellow' are actually Berger's. South had the excuse that Berger's had not been discovered then. I think he chose the nicest, brightest specimens he had access to and thus selected for the (much rarer in Britain) Berger's.

Generally speaking, Berger's is found more commonly further south. I used to think pale clouded was the commoner butterfly in the Swiss Alps but am not sure now. More investigation is needed.