Size: Wingspan 38mm
Where: Grassy mountainsides and gullies above 300m, for example Ben Lomond; Ben Vane; Breadalbane hills
When: Late June to early August on calm, sunny days
Walkers who are lucky enough to get a sunny day on the hill in early summer have the best chance of seeing these velvety-brown butterflies. Mountain ringlets are the country’s only truly alpine species – the first butterfly to recolonise the UK after the last ice age.
They may look small and delicate, but they are a tough and hardy species. The caterpillars survive one, and sometimes two, winters on the bleak, exposed mountainsides. They hide deep in the tussocks of mat grass that are thought to be their food plant, sometimes blanketed in snow for weeks on end.
The dusky-winged adults, which emerge from late June to mid July, are not so sturdy. They usually survive for less than a week, their lives devoted to finding a mate and laying the eggs for the next generation. The butterflies feed on the nectar of mountain flowers like tormentil or wild thyme, flying low to the ground to avoid being spotted by birds, which are their main predators.
Like some hillwalkers they only come out in warm sunshine, and if you see one mountain ringlet you may possibly see hundreds, as they often emerge en masse when conditions are right. It’s mostly the males you will see – the females are too weighed down by their eggs to fly often! The males will land on anything brown they spot – moss, sheep’s wool, even droppings – in the hope that it’s a female with which to mate.
Despite being one of our first colonisers, mountain ringlets are now found in only a small area of Scotland and in the central Lake District. Climate change could prove a threat to them in these last refuges, as warmer, wetter summers and milder winters could alter their habitat or affect their survival in other ways.
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