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 Apart from a few small colonies in the English Lake District, the small
mountain ringlet butterfly (Erebia epiphron) is restricted to the grassy and flower-covered mountain slopes of the central Highlands, notably the Breadalbane hills. Here it lives in colonies, especially in damp
stream valleys and usually between 1000-2500 ft above sea level, and on sunny days in late June and early July it flutters among the grass stems and feeds on flowers such as thyme. As soon as the sun
goes in the butterflies settle inconspicuously among the grass and their sudden disappearance seems almost magical.
The adult butterflies are a very dark brown with a series of orange marks, each with a tiny
black 'eye spot' near the edge of each wing. They are Britain's only true mountain butterfly and their dark colouring probably helps them to absorb the sun's heat quickly, enabling
them to warm up and fly. On the Continent many related species can also be found living in mountains. In Britain, however, the mountain ringlet's only close relative is the more lowland Scotch argus (E. aethiops).
The females lay eggs deep in clumps of mat grass (Nardus stricta). Given that this grass is found virtually throughout Scotland, it is not exactly known why the butterfly is so restricted
in its range. The grassy Breadalbane hills must have a special attraction that is not found on the more usual heather-clad mountains perhaps it is an abundance of nourishing nectar bearing flowers.
When the caterpillars emerge they feed at night, crawling up the stems to feed on the most tender shoots, and they then hibernate in the tussocks before feeding again the following
spring and pupating in May. Some of the colonies are very large and to date there has been little to threaten the butterfly in its mountain home, with the result that it remains reasonably
common within its restricted range. |
