A butterfly haven in an old limestone quarry

This is Ashes quarry, a former limestone quarry near Stanhope in Weardale that is now a wonderful nature reserve. The quarry floor is partially flooded and is a breeding place for dragonflies and damselflies, but this sheltered western end, which is mostly rough grassland and quarry spoil heaps, is always a good spot to look for butterflies.

It was good to see a small colony of wall browns has become established here. This is a butterfly that needs warmth and shelter, so this sun-trap, with its sun-warmed rock, clearly suits it very well.

Wall browns are very skittish insects, never settling for long in one place. This individual alternated between basking on its pile of rocks and feeding on herb robert flowers blooming amongst the stones.

The convenient supply of floral nectar meant that this one was constantly disturbed by rival males that tried to take over its domain. Wall browns are ferociously territorial, so each one of these incursions resulted in an aerial dogfight, as the butterflies spiralled upwards, so close to me that I could hear their wings clashing, before they separated and fluttered back to their respective territories.

Eventually a female arrived and courtsship began, with the pair walking through the grass and the male tapping the female with his antennae. I think the male is the closer of the two in this picture, with some wing edge damage that might have occurred during one of those bruising dogfights with a rival.

Wall brown colonies tend to be small and don't often persist in the same place for long, but this quarry site is sheltered and warm, with plenty of the caterpillar food plants (grasses), so it might last for a few years.

The warm piles of stones in the quarry are also excellent habitat for sun-basking common darter dragonflies ....

..... chirruping field grasshoppers Chorthippus brunneus

..... and this devil's coach-horse Ocypus olens. This beetle (more pics here) isn't often seen out and about in bright sunlight - it's more often seen in twilight.

Tandem dragonflies

We spent a fascinating afternoon recently watching dragonfly behaviour at Ashes quarry at Stanhope in Weardale.

The most numerous dragonflies in the shallow, moss-edged pools there are common darters, Sympetrum striolatum. We watched them on their egg-laying flights, where the male tows the female around, attached by the tip of his abdomen to a point just behind her head.

Coupling up like this is the male's way of defending the female he has inseminated, preventing rival males from mating with her and displacing his sperm.

It's an unwieldy arrangement. At frequent intervals the male lowers his abdomen, forcing the female down to the water surface where she drops fertilised eggs from the tip of her abdomen.

That's an awkward manoeuvre, when the male momentarily hovers in this vertical position.

The males are fiercely defensive of their territory, often perching on a favourite stone or ....

... plant stem, ready to drive off rivals and pursue any passing female.

The second commonest dragonflies at this site are black darters Sympetrum danae. There seemed to be quite a lot of interspecific aggro - we watched several aerial battles between the two species.

These dragonflies land with their wings outstretched but ....

... finally come to rest with them in this swept-forward configuration.

A Surfeit of Berries?

Back in the autumn of 2013 the local hedgerows were laden with berries but now most of those have been taken by members of the thrush family. So last week it was a surprise to find these wall cotoneaster Cotoeneaster horizontalis plants still carrying a spectacular crop of scarlet berries. The shrubs are growing in fissures in the cliff face in the old Ashes Great Limestone quarry at Stanhope in Weardale, in places that would only be accessible to birds. One large flock of waxwings could probably polish this whole crop off in a couple of hours. 

Cotoneaster horizontalis is native to western China and was introduced into British gardens in 1879. It was first recorded as a garden escape in 1940. It also grows on the walls of Stanhope castle, which about half a mile from the quarry.  

You can download a guide to the history of the quarry and to a circular walk around it by clicking here

Wildlife on Walls 11: Fairy foxglove, Erinus alpinus

This attractive little plant growing on the walls of Stanhope Castle in Weardale is fairy foxglove Erinus alpinus, a native of Central and Southern Europe that was first recorded on this spot in 1934. 

How and when it reached our shores is uncertain. Gordon Graham, in his Flora and Vegetation of County Durham (1988) quotes the following theory from W.J.Weston's The County of Durham, published in 1914;

"Round Edmondbyers the rare little pink flowers, a curious survival from the Roman occupation, may reward diligent search.It is supposed that the plant, which is found nowhere but in the neighbourhood of the camps was brought into the country by the Spanish legionaries"

For more wildlife on walls, click here.

Cup Fungus

We found this exquisite little cup fungus when we were out walking beside Shittlehope burn near Stanhope in Weardale at the weekend. It's growing on shady bare soil in woodland and is about 25mm. in diameter. It's a Peziza species, but I'm not sure which one. The moss growing beside it is a Fissidens species.

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.

A Lichen with Teeth

We found some very fine specimens of dog lichen Peltigera sp. when we were out  walking at Shittlehope Burn at Stanhope in Weardale this morning. I've often wondered why it's called dog lichen - I've found one or two references that suggest that Linnaeus gave it the Latin specific epithet caninus because he saw some resemblance to a dog in its shape, which I find hard to see, unless it relates to the menacing tooth-like structures, called rhizines, on the underside of the thallus.

The arrangement of the rhizines, which are extensions of the fungal part of the symbiotic partnership between alga and fungus that constitutes a lichen, are key identification features and as soon as I can get my hands on a lichen field guide I'll try to identify the species more accurately.

Some Peltigera species contain cyanobacteria that fix nitrogen in the symbiotic partnership, so the organism then has its own in-built nitrogen fertiliser supply and plays a part in the cycling of nitrogen in ecosystems.

Microcosm

In winter, it's the smaller things that tend to capture your attention on country walks - like, for example, this miniature garden of mosses, lichens and fungi growing on top of a drystone wall at Stanhope in Weardale. In the space of a few square inches there are toadstools (haven't identified the species yet - can anyone help me out with some suggestions?); at least four species of moss; at least three species of lichen. If you really got to work with a hand lens I suspect you could probably double the biodiversity count for this tiny patch .......... and if you resorted to using a microscope, who knows how many! Below are two of the larger ones that I think I can identify.....

This (I think) is an Orthotrichum species although I'm not certain yet which one..... most probably O.anomalum.

..... and his, with the distinctive hair-point extensions to the leaves and capsules that curl downwards into the moss cushion, is Grimmia pulvinata (with another moss on either side of it and Orthotrichum anomalum at the top and bottom).


It's a long time since I last tried to identify moss species.....................

A Trawling Caddis fly, a Hot Climb and a Railway Revival

This is Philopotamus montanus, aka the dark-spotted sedge, a caddis fly that we found on this morning's walk along Shittlehope burn, that flows down from the moorland above Stanhope in Weardale to the river Wear in the valley bottom. Most caddis fly larva live in a tube that they construct from plant material or grit, but this beautiful little caddis has an even more remarkable life cycle. The larva spends its formative years below waterfalls, where it spins a silken net that resembles a trawl net, attached to a rock with the mouth facing upstream, filtering out food particles that the current delivers.

The adult, more or a flutterer than an accomplished flier, is beautifully camouflaged against the dead leaves that still persist along the edge of the burn at this time of year.

And here's the dark-spotted sedge's preferred habitat, one of the many small waterfalls that punctuate Shittlehope burn's route to the river. The burn has carved out a steep-sided gorge whose banks are currently dominated by wild garlic, but other elements of the flora here include primroses, violets and globe flower - although it's a few years now since I've seen the latter here; it's much less often seen in Weardale than it is in Teesdale, the next dale south from here.

This is the middle section of the burn, before it cascades downhill. By the time we reached here we were pretty breathless - I'd forgotten what it was like to be too hot when out walking and today's soaring temperatures had us labouring a little as we headed uphill, but it was worth it because we reached the high pastures just in time to see...

... the 10.45am from Wolsingham chuffing into Stanhope station.

After a bit of a financial struggle the Weardale Railway is running regular steam-hauled services at weekends and the sight and sound of a steam train puffing up the dale marks the welcome return of a branch of the rural rail network that many believed had vanished for ever...