Switzerland, July 2009

Switzerland, July 2009

Switzerland, July 2009



Distribution

The worldwide distribution of this species - sometimes said to be the rarest in Europe - is restricted to a handful of colonies on both sides of the Swiss-Italian border, south of the Simplon Pass in Switzerland. Its haunts are famously inaccessible - vertiginously steep, rocky slopes and escarpments with scattered larch - and it is one of the hardest European butterflies to see. Fortunately, there are a few places where wandering individuals regularly cross paths and other more accessible areas, so with a little inside knowledge it is possible to find and photograph the butterfly. The best known site is the Laggintal, in Switzerland. Since 1985 it has been illegal to enter this valley carrying nets or other butterfly-capturing equipment, and in all sites the species is strictly protected against interference.

With a good view, identification is relatively easy. The red spots on the forewing are fused into a characteristic band and the dark spots within the red, on forewing and hindwing, are characteristically elongate, as if made with a cuneiform stylus. Beware, some small mountain ringlets have slightly elongate spots too, so this should not be used as a sole feature. The underside of the hindwing is greyish in the female - rather blacker in the male - with the outer half paler (though not as well demarcated as is shown in some of the books). Any black spots on the hindwing underside are naked - there is no red around them. The orange on the underside of the forewing reaches towards the wing base - especially visible in the female.

The larval foodplant is sheep's fescue and the life-cycle takes two season. Being a low-density butterfly at the best of times, this means it may locally be more abundant in alternate years. Certainly, I saw this species only in odd years for a long time. Then I was lucky enough to be shown a new site in 2018, when I saw several individuals, and on returning in early July 2019 found a fresh male at the same site. So at that site at least, I have even and odd sightings. Tolman gives the flight period as late June to early August. My earliest sighting is 6th July (the male seen in 2019) and I have never seen one after the middle of July.