heather moorland in August

 The moorlands of Weardale are a sea of purple heather at the moment, often stretching all the way to the horizon. Billions of tiny, nectar-rich flowers are in bloom, feeding vast numbers of insects, from minute thrips to butterflies.

The flowering of the heather coincides with the breeding season of these heather Colletes bees (Colletes succinctus), below. They lay their eggs in tunnels excavated in the sandy moorland soil, usually on a south facing patch of bare ground, then provision the egg with heather pollen before sealing the chamber. They're solitary bees, unlike the highly organised, social nests of honeybees and bumblebees, but do aggregate their nests in huge colonies. Yesterday we must have walked past many thousands of them, congregating at the entrance to their tunnels and shuttling backwards and forwards to the heather flowers.

The vast expanse of flowers also attracts butterflies. Yesterday we saw red admirals, small coppers, small tortoiseshells and small heaths. The small coppers breed on dense, transient patches of sorrel that grows quickly on the bare soil after a heather burn.

This 'woolly bear' caterpillar (below) is the larva of the northern race of the oak eggar moth Lasiocampa quercus. It spends two years in the larval stage, overwintering as a larva before emerging to feed again, then pupating over a second winter before it finally emerges as a spectacular moth.

And finally, a rove beetle Platydracus stercorarius, with wings tightly folded under those red wing cases

Heather

We walked over the moorland north of Blanchland on the Durham/Northumberland border today, when the blooming of the heather was at its peak. A sea of purple, with golden patches of wavy hair grass and bright green Polytrichum and Sphagnum mosses in the spaces in between.

Fox moth caterpillar

This fox moth caterpillar Macrothylacia rubi crossed our path when we were out walking on Birkside Fell near Blanchland in Northumberland this morning. It will have been feeding on heather.

It's quite late in the year to see one of these in such an active state but the unusually warm weather might have coaxed it out. It's pobably searching for a sheltered spot to spend the winter, before emerging for a brief bask in spring sunshine and then pupating.

There are pictures of the adult moth here.

Heather as far as the eye can see

A few pictures of the heather moorland above Blanchland in Northumberland looking fabulous this morning. Surprised to see peacock butterflies nectaring out on the heather.

Muir burning .....

Muir burning in Teesdale yesterday - burning off the old heather stems so that new shoots develop, to feed grouse. A period of dry weather and light winds produced good conditions for these controlled fires.

Click image to enlarge.

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.

Purple Haze

Heather, or Ling, Calluna vulgaris

Heather moorland

The heather moorlands in the North pennines are just about at their best now, with hundreds of acres of hillside clad in billions of tiny purple flowers. Although heather moorland looks like a uniform sea of purple there are three different species that contribute to the purple haze that shimmers on the fellside on a hot summer afternoon. Cross-leaved heath (Erica tetralix) grows in the boggier patches and flowers first, followed by bell heather (Erica cinerea) and ling or true heather (Calluna vulgaris) which both grow on drier soils. Flowers of the first two species are distinctly bell-shaped and in bell heather they’re concentrated in clusters at the shoot tips, whereas in cross-leaved heath they tend to be distributed more uniformly down the stem. The leaves of cross-leaved heath are distinctive too, arranged in whorls of four. Ling, in the close-up photograph above, is far the commonest of the three and has more densely packed, paler, smaller flowers distributed over long lengths of stem, with leaves that are tiny in comparison with the other two species. The heather moorlands of the north Pennines are skilfully managed by cyclical of burning in strips, removing the old, moribund heather. The fast-moving fire burns away the old heather without killing the roots, which then regenerate tender new shoots that are an important element in the diet of red grouse. Burning in strips creates a varied habitat with a mosaic of age structures, providing a habitat for a wonderful range of birds, insects and reptiles............more of them anon.