Return of the native

Catching sight of a speckled wood butterfly isn’t a big deal in many parts of the country, but up here in County Durham it was, until about three years ago, something to get excited about. Until the 1840s this butterfly was quite common in the region, then it went into steep decline. When Tom Dunn and Jim Parrack published ‘The Moths and Butterflies of Northumberland and Durham’ in 1986 they considered it to be extinct in both counties but wistfully noted that “since it still survives in Yorkshire it is theoretically possible for it to return”. How heartening, then, to find that over the last few years it has recolonised both counties, moving rapidly northwards. It seems that climate change is the reason. I photographed this one in Durham University Botanic Garden yesterday.

The Jewel Mines

Throughout the eighteenth and nineteenth century, Weardale was a major centre for lead mining. Lead ore was extracted from narrow veins in the rocks and tens of thousands of tonnes of spoil were hauled out of tunnels by ponies pulling trucks carried on wooden rails. It was tipped at the end of the tracks, creating fan-tails of spoil that can cover whole hillsides, as they do in this photograph taken at Cowshill last weekend. Weather constantly erodes the heaps, revealing beautiful amythyst-coloured crystals of ‘fluorspar’, or fluorite amongst the spoil. When our kids were little they used to bring back pocketfuls of these ‘jewels’ from ‘the jewel mines’. Some of the finest crystals – like those at http://www.ukminingventures.com/WeardaleMines.htm

- are sought after by collectors. Footpaths and bridleways across the dale are decorated with fluorspar fragments that look their best after a light shower of rain, glittering in the sunlight.

Mountain pansies

We made the long, steep, breathless climb up the northern fellside from St.John’s Chapel today, almost to the top of Black Hill. The views back across Weardale to Chapel Fell were stunning, we were accompanied by the bubbling calls of curlews during most of the ascent and as an added bonus heard our first cuckoo of spring in a pine plantation, about 500 metres above sea level. There are plenty of nesting meadow pipits on these fells for it to parasitise. Apart from bird song, the only sound when you reach the top is the wind. Otherwise, silence. But the purpose of the climb wasn’t to admire the views, seek solitude or listen to the birds, but to see if the first mountain pansies were in flower. And they were. It’s hard to imagine a bleaker landscape than the tops of these fells, where most of the vegetation is still brown and withered after a hard winter, but from mid-April onwards thousands of these delightful flowers decorate the short turf wherever there is a little shelter, turning it into a natural rock garden. Currently they are just about the only flowers in bloom at this altitude. Search amongst them and you can find every flower colour, from deep purple through yellow to pure white, sometimes with all three colours on different petals of a single flower. Well worth the climb.

Two heads better than one?

Found this twin-headed dandelion with a wide, flat flower stalk yesterday. There are usually four possible causes of this kind of abnormality: (1) A mutant plant – but if it was a genetic mutant all the flower heads would have been like this, not just one. All the other flowers on this plant were normal. (2) A sub-lethal dose of herbicide – but there were no signs of herbicide damage in any of the surrounding vegetation. (3) A soil bacterium called Corynebacterium, which causes the fasciation sometimes seen in twigs of woody plants like Forsythia, where the stem is wide and flat instead of having a circular cross section – a possibility. (4) Damage to the bud during the earliest stages of development, perhaps by an insect – my favourite theory, in this case.

Pillbug

This pillbug crossed my path today, trundling across the ground like a miniature armoured siege engine. It curled up in a ball in the palm of my hand when I picked it up, revealing the smaller tail segments that distinguish it from the superficially similar pill millipede (which also has many more legs). It's about as close as we get to an armadillo in Britain - which is reflected in its Latin name, Armadillidium vulgare .

The importance of the commonplace

Naturalists tend to be obsessed with rarities but it’s the common species that are the foundation of all ecosystems. The billions of dandelions flowering now – common and so taken for granted - provide a reliable source of pollen for honeybees and other insects just when they need it most. Rare species are generally those that are at the natural limits of their range of climatic tolerance anyway, and so come and go according to the vagaries of climate, but it seems to me that we should be most concerned when common species that play a pivotal role in ecosystems become less common – that is a symptom of potential catastrophe. Loss of old pastures has led to a rapid decline in cowslip populations in many parts of the country, but this can be reversed. I found this wonderful display of cowslips – deliberately seeded – just outside of Durham city today. This was a patch that was roughly the size of a medium-sized back garden; imagine what a five acre pasture with a population of cowslips like this would look like. They do still exist - I know of a few in the north east, although none are quite as denslely populated with cowslips as this. The wild plant conservation charity Plantlife has a well established common plants survey that anyone can contribute to – take a look, at http://www.plantlife.org.uk/uk/plantlife-get-involved-common-plants-survey.html

Now is the perfect time to get involved.

This way madness lies...

Spent a hot and frustrating afternoon chasing hyperactive bee-flies around the garden, as they visited the forget-me-knots and lady’s smock flowers around the pond. Never really got the picture I was hoping for, but made an interesting discovery - take a look at the middle picture (double-click on image for a larger version). There’s a step change in the thickness of this insect’s long, straight proboscis (see top picture) and where this step-change occurs the narrow, pointed tip splits apart into a Y-shape when it withdraws from the flower. I’m guessing that when the two halves are brought back together again this reforms a narrow tube that draws up nectar by capillarity, and that this splitting-and-reforming operation prevents the formation of airlocks in the hollow proboscis. A high shutter speed reveals what the human eye can never see, even though it means that the photos have a very shallow plane of focus.

Wall plants

Inland cliffs are a relatively rare habitat in many parts of Britain but man-made walls are equally acceptable for most cliff-dwelling plants. These two species – ivy-leaved toadflax (aka Kenilworth ivy) and yellow corydalis - are currently in flower on walls around Corbridge in Northumberland. Neither are native – both come from continental Europe – but they’re a welcome addition to our wall flora and put on a good display from spring onwards. Both thrive on walls here and ivy-leaved toadflax has a neat trick of developing fruit stalks with an aversion to light, so that they grow into dark wall crevices and deposit their seed there. The corydalis seed capsules simply burst to scatter their seed, but first the flowers need to be pollinated and today this mining bee seems to have been performing that role – does anyone know what species of bee it is?

Goosander and dippers

Downstream from the picturesque medieval village of Blanchland - see http://www.blanchland.org/ - Northumberland's River Derwent races over three kilometres of stony riverbed before it empties into the managed confines of the Derwent Reservoir. It’s perfect dipper habitat and today we mapped the territories of two pairs along this wild stretch of river. Mapping dipper territory is relatively easy – just follow them along the river until they do a U-turn and race back past you; they won’t cross into another’s stretch of river once ownership has been established. We never got close enough for a really good photograph, but close enough to record one of this bird’s remarkable features: white eyelids. When a dipper blinks its eyes go bright white. We also encountered a pair of goosander that are probably nesting along this stretch of the Derwent and just managed a shot of the handsomely-plumaged drake as it streaked past.

Up on the fell tops..........

We followed a circular route today, up onto the flanks of Chapel Fell from St.John’s Chapel in Weardale, then down to Ireshopeburn and back along the River Wear. We could hear golden plovers’ plaintive calls through the haze, coming from the rough, boggy pastures near the fell top but the lapwings, further down in the grazed pastures, were much more vociferous, with their squeaky alarm calls and that strange creaky, groaning noise that their broad wings make as they beat the air during their wild aerobatics. They’ve already laid eggs and have a hard time defending their nests against crows; we found one egg smashed and eaten, with tell-tale beak marks, and watched the desperate lapwings driving off repeated incursions from their tormentors. There don’t seem to be as many lapwings holding territories on the fell as I can remember in previous years.

....and down in the valley

Sycamore buds are just beginning to burst on the trees in the valley bottom in Weardale, and there are some fine displays of aubretia in the drystone walls beside the river. We found yet another smashed egg, possibly of a house sparrow (?) – with peck marks that reveal that it was another victim of an egg thief.

Turning the Tide

If Michael Caine returned to the Durham coast today, south of Seaham, he probably wouldn’t recognise it. The final scenes of his cult movie Get Carter were filmed along this coastline in 1971, and in those days it was an industrial hell-hole. Coal waste from the local mines was dumped on the beaches, which resembled a moonscape: parts of the movie Alien lll were shot here, because it was the bleakest landscape that the movie-makers could find. Today, thanks to the inspired Turning the Tide campaign (http://www.turning-the-tide.org.uk/), the damage is being undone and the path through the cliff-top grasslands is already a delight, flanked by wildlife at every turn. This morning the air was full of the coconut scent of gorse, masses of blackthorn blossom attracted peacock butterflies, skylarks sang and kestrels hunted for voles. The magnesian limestone grassland along this coastline, south of Seaham, puts on a magnificent display of wild flowers from April onwards and I’ll be posting more photographs later in the season, when I make return visits. In the photographs above you can see the little alula feathers, on the leading edge of the kestrel's wing, that prevented it from stalling while it hung in the air, on the updraft from the cliffs.

Recovery

There are two reasons for posting this picture of the familiar orange tip butterfly. The first is that thirty years ago, when I first moved to the North East, this was an uncommon butterfly here. Seeing one was something worth getting excited about; now they are very common and even breed on lady’s smock, dame’s violet and Jack-by-the-hedge in my garden. The second is that this photograph, taken today of the first orange tip I’ve seen this year, newly emerged and pristine, was taken in urban Newcastle, on a grass verge beside the lower reaches of the Ouseburn, just before it reaches the Tyne. The lower Ouseburn was once one of the most polluted stretches of river in Britain and until the mid-20th. century was flanked by a devil’s cauldron of industries that dumped waste into its waters. Now it’s well on the road to recovery. I regularly see kingfishers there. So the orange tip shown here symbolises a wildlife good news story – the expansion of a butterfly’s range and habitat recovery. To read more about the Ouseburn’s history, visit http://www.ouseburntrust.org.uk/

Perfect Weather for Windflowers

Bright and breezy today, perfect weather for the wood anemones Anemone nemorosa, which are in full flower in woodlands around Durham city. Its scientific name comes from the Greek word for wind, anemos, and when a gust blows across the woodland floor thousands of anemone flowers shiver on flower stalks that are as slender as a thread. Many modern books on British wild flowers repeat the story that the Roman naturalist Pliny (c. 77AD) believed that it was the wind that brought anemones into bloom in the spring ("The flower never opens, except while the wind is blowing, a circumstance to which it owes its name"); however, it wouldn't have been this species that he had in mind, but the far more robust, scarlet-flowered Anemone coronaria that blooms throughout the eastern Mediterranean in spring. Pliny's writings are fascinating source of natural history information, some of it fanciful, some of it accurate and perceptive. You can consult them on-line at http://www.perseus.tufts.edu/cgi-bin/ptext?lookup=Plin.+Nat.+toc

Coot

A coot, creating ripples amongst the reflected reeds at Durham Wildlife Trust's Low Barns Nature Reserve, near Witton-le-Wear. Double-click on the picture for a larger image.

Sticklebacks

The walkway built out over the new wetland area at Durham Wildlife Trust's Low Barns Reserve at Witton-le-Wear offers excellent opportunities for watching the courtship dances of sticklebacks in spring. A male fish builds a tubular nest in the shallow water from bits of weed, then defends his territory from other males until he's enticed a female to swim through his nest and lay eggs inside. Males guard their nests, fanning water over the eggs, until they hatch. You can watch movies of the whole sequence at

http://www.arkive.org/three-spined-stickleback/gasterosteus-aculeatus-aculeatus/

Slime moulds

These spectacular examples of the slime mould Reticularia lycoperdon are currently to be seen on the trunks of an alder, in the Long Alder Wood at Durham Wildlife Trust's Low Barns Nature Reserve at Witton-le-Wear. These are the most spectacular examples of this weird organism that I have ever seen. It begins life as a swarm of microscopic, amoeba-like organisms that slither over tree bark, engulfing bacteria. Eventually they aggregate to form these white, tear drop-like blobs that form a hard white skin and produce millions of powdery spores inside, that are dispersed when the skin ruptures. Each spore germinates to form another amoeba. Each of the white blobs here is about the size of half a tennis ball; I have never seen so many in one place. You can find out more about Low barns Reserve at http://www.durhamwt.co.uk/LowBarnsVisitorCentre.htm

and more about this slime mould at

http://www.discoverlife.org/20/q?search=Reticularia+lycoperdon