Mountain Ringlet (Erebia epiphron)
The Mountain Ringlet (E. epiphron) is probably one of our most difficult species to see. It is only found in discrete colonies in remote locations, has an extremely-short flight period (a few weeks only) and can be difficult to find in anything other than warm bright weather, since the adults tend to remain sheltered deep in grass tussocks in overcast and cool conditions. Given the right temperature this butterfly will take to the air as soon as the sun shines, bringing an apparently dormant landscape to life. As its name suggests, this butterfly is found in mountainous areas, typically at altitudes between 450m and 800m AMSL though can be found at both lower and higher levels; as per the example figured (from around 350m AMSL). E. epiphron forms discrete colonies in particular areas of the mountains they inhabit and, on good sites, may be seen by the hundred. This is typical of epiphron - localities may be few and far between, but where they occur the butterfly is often found in abundance.
E. epiphron is found in two main regions in the British Isles. In England, it is found in the Lake District of Cumberland and Westmorland. It is also found in western central Scotland, primarily in the counties of Argyllshire, West Inverness-shire and Mid Perthshire with a few scattered colonies elsewhere. It is surprisingly absent from Snowdonia and the Pennines. On the basis of four specimens in total (seven are reputed, with four considered by most authorities to be genuine), this butterfly is also thought to have occurred in Ireland (see references below).
There is one generation each year, with adults emerging at the start of June in the Lake District and early July in Scotland.
A recent visit to Irton Fell, with my good friend Peter Eeles, produced numbers in excess of 150 (a male is figured above), with the peak of sightings being achieved on the higher slopes close to Greathall Gill and Whin Rigg. We were particularly pleased to watch a female ovipositing on Mat-grass (Nardus stricta). The eggs, which are pale cream at first, develop red-brown blotches after a few days. They are relatively large compared with the size of the butterfly, with each female laying up to 70 eggs. This stage lasts around two or three weeks depending on the weather
A beautiful butterfly in fabulous surroundings …