Small Coppers: warm colours and fiery temperament

Today's Guardian Country Diary is about small copper butterflies.

This last week of unbroken sunshine has produced some excellent opportunities to watch these lively little butterflies. This was one of two contesting a sunny, south facing slope on the moorland edge near Stanhope in Weardale, where some heather was still flowering.

These are amazingly aggressive little butterflies and this individual rose several times from its favourite sun-bathing stone to chase off its rival. What really surprised me was how fast and furious these aerial battles are - I've often watched fighting male butterflies but this was the first time I had seen and heard a clash of wings.

The lower slopes of heather moorlands offer some of the best opportunities for watching the late summer generation of small coppers in Weardale because there is plenty of nectar available from heather flowers and also usually plenty of sorrel, their larval food plant. It seems to be especially prolific in the year after heather burning, maybe because the minerals in the ash promote very vigorous sorrel growth.

The other abundant nectar source for them at this time of year at lower altitudes is devil's-bit scabious, which has a long flowering period. 

A Butterfly Bank.....

Along the old disused mineral railway line between Garmondsway and Trimdon Grange, on the magnesian limestone in east Durham, there's a 200 metre south-facing stretch of embankment that's near perfect habitat for the the limestone flora and its associated butterflies.

When we visited last week the first generation of small coppers had just emerged. This one is sunning itself on one of last year's carline thistles - a very painful plant to kneel on when you are trying to take a photograph.

The bank is also an excellent site for the dingy skipper butterfly which, despite its derogatory name, is very attractive when it settles for long enough to be examined at close quarters. Chasing butterflies around on a hot day is frustrating and unproductive, and can only lead to extensive tramping of the flowers, so I just sat and waited for the butterflies to come to me. Dingy skippers like to sunbathe on patches of bare soil and sure enough a female settled right next to me, soon to be joined by a male, on her left here.

Once she recognised that she was being courted she cocked up her tail and opened her scent glands, releasing pheromones that are the butterfly equivalent of Chanel No. 5, to secure his undivided attention. Double click this and the above image for a large, clearer view.

This is the butterfly bank in question.

At the moment it's dominated by drifts of common hawkweed Hieracium vulgatum but some of the choicer limestone flowers are coming out, such as .....

..... common milkwort Polygala vulgaris , and ....

..... and spotted orchid, growing here amongst salad burnet.

Muir Burning

In late winter this is a common sight in the northern Pennine dales: muir burning -burning away patches of old, woody heather. This encourages the growth of fresh, palatable new heather shoots, that are essential for the survival of red grouse at these high elevations. Muir burning is a highly skilled process, ensuring that the fire moves fast enough to burn away dead wood without killing the roots or setting fire to the peat if the ground is too dry. If you double click on this image to enlarge it you should be able to see the geometric outline of a black recently-burned patch and the browner outline of one of last year's burns.

The end result is a patchwork grouse moor landscape like this one between Edmundbyers and Stanhope in Weardale. When flowering time comes around in July you see a similar patchwork, but now in shades of purple heather flowers. 

Double-click for a clearer image of this picture and the next.

The grey areas here were probably burned during winter and have yet to regrow - the umber areas are older heather with new shoots, in peak flowering condition, that will hum with bees when it blooms.

For a year of two afterwards there's often a flush of growth of sorrel plants in the fertile ash released by burning, which in turn are colonised by small copper butterflies. Some of the best small copper populations that I've found in the uplands have been in landscapes like this.


These upland areas are also breeding grounds for curlew and golden plover and hunting grounds for merlin.