Early Spring on the Durham Coast

One of the pleasures of living in a county like Durham, whose topography stretches from sea-level on the coast to the high Pennine hills that form the backbone of England is that you can extend the pleasures of spring. Today these primroses were in full flower on the edge of the sea cliffs just south of Seaham but it will be anything up to a month before the same species reaches this stage of development in the more exposed parts of Upper Weardale - offering opportunities for enjoying them over an extended period.

These violets were in bloom a little further along the cliff edge. I think this is hairy violet Viola hirta because I couldn't retect any scent, although you can never discount the possibility of the presence of sweet violet V. odorata genes, as these two early-flowering species hybridise.

Sunday's sunshine brought out the gorse flowers on the cliffs, with their distinctive aroma of coconut.

There were hundreds of coltsfoot blooms in the grass on the cliffs. The leaves won't appear for a couple of weeks, only expanding after the blooms begin to fade. The plant spreads via a creeping underground rhizome, so when you see a fine display of coltsfoot flowers covering a large area, to appreciate the full extent of the plant you need to imagine the network of underground rhizomes that connect them all together.

The flower buds of blackthorn (sloe) on the cliffs were on the point of bursting but I had to look hard to find one that had opened...

 This is a stonechat, perched on the thorn scrub and in fine voice, and ......

.... here's another, in handsome breeding plumage. 

When I turned over one of the limestone boulders down on the beach at Hawthorn Hive I found a family of pill bugs Armidillidium vulgare.

 When they find themselves threatened these little armoured crustaceans have a neat trick......

They curl themslves up.... 

....into an almost perfect armoured sphere and simply roll away into the grass....

Grasshopper

We came upon this male field grasshopper Chorthippus brunneus sunbathing on the steps down to Hawthorn Hive on the Durham Coast, this afternoon. His courting days are over and he was making the most of the warm mid-day sun, before the frosts arrive and bring an end to his short life. Somewhere there will be packets of eggs, carefully inserted amongst grass roots by his mate who he would have serenaded by sawing the pegs on his legs back and forward across those membranous wings, in the process of stridulation.  Next spring they'll hatch and the nymphs that emerge will grow and moult four times before they reach maturity - and then the next generation of chirruping grasshoppers will begin the whole cycle all over again.
You can listen to a field grasshopper's song here

For more grasshoppers, click here

Butterfly Haven

Today's Guardian Country Diary is an account of a visit to Hawthorn Hive on the Durham Coast, just south of Seaham. As soon as you start to descend the steep steps down to the beach you leave the cool south-westerley prevailing wind behind and find yourself in a sheltered bay, looking outwards towards the North Sea horizon. Until about thirty years ago the bay was used for dumping colliery waste (you can still detect a whiff of coal and find colliery artifacts, like bits of conveyor belt), but since that stopped it has gradually recovered. The shelter and warmth at the base of the cliffs provides a haven for wild flowers and insects - notably butterflies.

Down at the cliff base the warmth and shelter encourage early flowering and rapid seed development. These downy rose hips were ripe and already beginning to soften.

This is the seed head of a greater knapweed (Centaurea scabiosa) plant. It's particular warm close to the limestone cliffs, thanks to the reflected heat of the sun, and there the dry seed heads open into this star-shaped conformation, releasing the seeds. You can see a couple of seeds, with their pappus of bristles, still there in the centre.

There's a wealth of limestone-loving native wild flowers down on the beach and one notable alien introduction - a massive clump of montbretia (Croscosmia x crocosmiiflora). The parents of this garden hybrid orginated in South Africa. It's a bit of a mystery how the plant reached this bay, which is a long way from the nearest house garden, but it thrives at the base of the cliffs, where the temperature when this photograph was taken must have been close to that of its ancestral home.

Bees visit the montbretia flowers but most of the butterflies, like....

.... this peacock, which was drawn to the knapweed ....

... and this one, feeding on the dense patches of devil's bit scabious just below the cliffs ....

.... feed on the native wild flowers. On this visit we counted 16 species of butterfly, including commas (above), small whites, large whites, green-veined whites, small coppers, common blues, red admirals, peacocks (in large numbers), small tortoiseshells, meadow browns, a single painted lady, wall butterflies, speckled woods, small heaths, ringlets and a large skipper...............................but definitely no heath fritillaries - the photograph of these butterflies that accompanies the piece in the on-line Guardian is pure fantasy on the part of the newspaper's picture editor - there are no heath fritillaries in the north east, or indeed anywhere north of Essex.

 There are more accounts of the flora and fauna of Hawthorn Hive at http://cabinetofcuriosities-greenfingers.blogspot.com/search/label/Hawthorn%20Hive

Ruby-tail wasp

In my last post I outlined the gruesome breeding habits of the spiny mason wasp, that provisions its nest with paralysed weevil grubs for its larvae to feed on at a later date. In the spirit of Jonathan swift's famous observation, that....

 naturalists observe, a flea

Has smaller fleas that on him prey;

And these have smaller still to bite ’em;

And so proceed ad infinitum.

... here is the mason wasp's nemesis, the magnificently be-jewelled ruby-tail wasp Chrysis viridula. I watched this deadly little parasitoid's behaviour while I was photographing the mason wasp's nest, at the base of the cliffs at Hawthorn Hive on the Durham coast.

There are many species of ruby-tail wasp, also known as cuckoo wasps, each a parasite of a particular species of host wasp, and one thing that they have in common is relentless, restless activity, constantly using their downward-curving antennae to pick up a scent trail in the soil. Ruby-tail wasps have a thickly armoured, iridescent exoskeleton that's impervious to the stings of an angry victim. This species is less than a centimetre long and its colours are more exquisite than anything a jeweller could create.

Once it finds its host's nest hole it uses its antennae to explore the entrance, presumably testing for the specific scent that identifies its prey. Recent research suggests that ruby-tails can produce compounds in their exoskeleton that mimic the scent of their host and so avoid detection and counter-attack.

Next the ruby-tail crawls head-first into the nest hole, to make sure there's no one home, then ....

....... it climbs out and reverses in ....

... until only its metallic green head is visible in the entrance. Inside, it lays eggs that will hatch and produce larvae that will eat its host's young and their weevil grub food store. The hapless host , returning to seal its nest, will never know that the ruby-tail has visited and that its young are doomed.

Buried Alive

This (I'm pretty sure) is a spiny mason wasp Odynerus spinipes , which I found amongst the bloody crane'sbill flowers at Hawthorn Hive last weekend. Notice the distinctive antennae, curled into a spiral at the tip.

And this is its nest hole. The sandy soil that collects on rock ledges at the bottom of the cliffs at Hawthorn Hive offers a perfect, sheltered breeding site. Mason wasps dig a tunnel and lay their eggs in underground chambers, which they provision with paralysed weevil larvae - a living larder for their grubs to feed on when they hatch. The wasp build a cowl-shaped tube over the entrance to the nest hole, seen here in the early stages of construction, but once the nest hole is provisioned and sealed the cowl crumbles away. Its breeding methods may be gruesome, but before that nest hole is sealed it's often visited by another wasp with equally horrifying habits and a truely stunning colour scheme.............

............to be continued.

Butterfly Hot-Spot

A visit to Hawthorn Hive on the Durham coast at the weekend coincided with the recent emergence of several butterfly species, including this pristine male common blue and .....

.... and its rather more muted female consort.

The raised beach at Hawthorn Hive - a legacy of past colliery waste dumping - is covered with large patches of bird's foot trefoil, food for common blue and dingy skipper caterpillars, so this sheltered bay is a great spot to find both species - and also several others. The cliffs provide shelter from the wind, unless it's blowing from the East - and the prevailing wind is mostly south-westerley. Paradoxically, it's only the raised beach - produced by past industral activity - that protects this wonderful site for flowers and insects from being inundated by the waves. It's slowly being eroded and once it has gone the waves will be able to reach the base of the cliffs where.....

..... this green-veined whire was collecting nectar from bloody crane'sbill flowers...

...... while this large skipper basked on the same plant's foliage....

... and another .... amongst the grasses.

On the cliff tops above small heaths were flying in the grassland. They have a very distinctive way of sunbathing. Most butterflies orientate themselves with their back to the sun and open their wings to absorb the heat - like the common blues and large skipper above. Small heaths keep their wings folded but turn their whole body at 90 degrees to the sun's rays, so the underside of the wings on one side of the body only faces the sun.

Hawthorn Hive

The landslips on the beach at Hawthorn Hive on the Durham coast (above) have a fascinating limestone flora, where the shelter of the cliffs often coaxes plants into flower early.

Last weekend we found the first bloody crane'sbill flowers opening ...

 

... at the same time as the last of the dog violets were beginning to fade ....

..... while common milkwort was also just coming into bloom

 

... and glaucous sedge was also flowering. The upper flower spike on the sedge carries the stamens that have already shed their pollen, while the lower two flanking it are female, identifiable by the feathery white stigmas protruding from them. Sedges are easily identifiable by the triangular cross section of their stem - roll the stem between finger and thumb and you can feel that it's three-sided.

Meanwhile, twayblade orchid flower buds are still developing, and it will be a week or two yet before they open.

Not so Dingy Skipper

Most observers agree that the dingy skipper Erynnis tages is a declining butterfly, so it was encouraging to find a small colony at the base of the cliffs at Hawthorn Hive last weekend. This butterfly has two key requirements - bird's foot trefoil as a caterpillar food plant and bare ground for the adult to bask on. Its colour scheme makes it hard to spot but under close scrutiny it's far from being dingy, with those beautiful mottled shades of brown and even a hint of pale blue in the fringe around the edges of the wings. I'm intrigued by those tufts of 'hair' on the hind wings, near the abdomen. I think this is a male - apparently distinguihed by that line of yellowish scent scales along the leading edge of the fore-wing.

A Flower for our Financial Times?

These delightful sea pinks Armeria maritima were beginning to come into full bloom along the Durham coast at Hawthorn Hive at the weekend.

The alternative common name of sea pink is thrift, although no one seems quite sure why this came about. Richard Mabey, in his Flora Britannica, suggests that it may have been because its tufted leaves were economical with water in the windy locations where it's commonly found.

Those, like me, who are old enough to remember pre-decimalisation currency will recall that some of the old 12-sided brass threepenny pieces carried the botanical embled of a thrift plant on the back, as a reminder of the importance of being prudent with money. Bearing in mind the current economic predicament of the country, maybe it's time to use the same emblem on today's currency?

Stalking Tigers

The crumbling magnesian limestone cliffs along the Durham coast are excellent places to find these tiger beetles Cicindella campestris. There were scores of them running over the rock-falls at the base of the cliffs at Hawthorn Hive today.

Their exoskeletons are beautifully iridescent, shot-through with a purple sheen when the sunlight strikes them and their movements are distinctive too, rapidly running over the soil surface in a state of constant agitation and often taking to the air for short flights when they’re disturbed.

These insects are ferocious hunters, like most ground beetles, running down their prey and impaling it on needle-sharp jaws (double-click bottom image for a better view of these). When she was a child my daughter made the mistake of catching one of these jewel-like beetles in her cupped hands and instantly regretted it when it sunk its jaws into her finger. Twenty years later, she still remembers the pain it inflicted. Their jaws have a very wide gape and these pictures reveal a possible reason - the male uses them to cling onto the female when they're mating, grasping her at the narrow junction between her thorax and abdomen. The jaws of the larvae, that live in vertical shafts in the sandy soil, are equally impressive and are held level with the soil surface, ready to snap shut on any small insect that blunders too close to the burrow entrance.

For some pictures of another ground beetle in unfortunate circumstances, take a look at http://cabinetofcuriosities-greenfingers.blogspot.com/2009/07/food-that-fights-back.html

An Industrial Legacy

Just south of Seaham on the Durham coast (see http://cabinetofcuriosities-greenfingers.blogspot.com/search/label/Durham%20Coastal%20Path) there’s a little bay called Hawthorn Hive, reached by a steep cliff path. The Magnesian limestone is constantly eroding here, creating small landslides that bring down the flora and fauna from the cliff tops to beach level. There it’s completely sheltered from the south-westerly winds that blow across the cliffs for most of the time, so the display of wild flowers and butterflies at the back of the beach is simply wonderful. Pictured here, from top to bottom, are carline thistle, yellow-wort and rest harrow. This is one of a number of delightful bays along this coast that were once used for dumping colliery waste, that are well on the way to being fully restored to their former glory, but ironically the narrow zone of biodiversity at the base of Hawthorn Hive’s cliff depends on past industrial pollution. Here coal dumping created a raised beach that stops the waves from reaching the base of the cliffs (bottom two photographs). With rising sea levels, once the sea finally sweeps away the last of the colliery waste (and it’s eroding quite rapidly now), the days of the present cliff base flora and fauna will be numbered. There’s a little more about this at http://www.guardian.co.uk/environment/2009/aug/06/seaham-coast-colliery-waste