Some Cotswold places
And butterflies in their disorder ...
Laurie Lee
The Cotswold Hills lie on Jurassic Limestone and run north-east from Jane Austen's Bath up towards Shakespeare's Stratford-on-Avon. They consist of a steep west-facing escarpment, and a broad gentle dip slope that runs away eastwards towards Oxford and is dissected by a series of minor river valleys. Today, away from the steeper slopes the Cotswolds are dominated by arable farming, but long ago this was the centre of the medieval wool trade. The legacy of wool, and its associated wealth, is illustrated by the spires of churches, built ostentatiously from honeyed Cotswold stone. The slopes are either wooded, mainly with Ash or Beech, or covered in limestone grassland. After Rabbits were killed off by myxomatosis most of the grasslands, or ‘banks’ to use the local name, became dominated by coarse grasses and scrub. Many slopes reverted to Ash woodland.
One of the largest and richest areas of limestone grassland is Rodborough Common, a 100-hectare (250-acre) promontory that towers above the suburbanised Stroud valleys and which adjoins the flatter, archaeologically rich Minchinhampton Common and its small satellite commons. These commons are owned by the National Trust and are designated as SSSI. Rodborough is also a Special Area for Conservation, the only limestone grassland SAC in the Cotswolds. The commons are grazed by cattle run by local commoners, between early May and the autumn. Although Minchinhampton Common is quite heavily grazed, certainly from a butterfly perspective, the steep flanks of Rodborough are decidedly under-grazed, as stock only venture off the flat top during summer droughts. To counter this, in 1999 the Trust developed a conservation herd of Belted Galloway cattle which grazed the slopes inside temporary electric fencing pennings. The commoners have now taken over the running of this essential herd.
Rodborough was given to the National Trust in 1937 by Thomas Bainbrigge Fletcher (1878–1950), former Naval Paymaster and, later, Imperial Entomologist in India – surely the most glorious title the Empire and the Raj ever combined to produce. Bainbrigge Fletcher was a well-respected figure in entomology and a specialist in micro-moths. Consequently, he persuaded many of the leading entomologists of the interwar years to survey his land. Today, Rodborough seems hugely proud of its entomological heritage and makes visiting entomologists welcome.
As is the case in most of the Cotswolds, Rodborough's steep slopes are dominated by Tor-grass and Upright Brome grass (CG5 in the language of the National Vegetation Classification), though prevalent thin soil conditions mean that these thuggish grasses only become genuinely rank where deeper soil has collected along the old cattle-walk terraces that traverse the slope contours. Amongst these rough grasses exists a rich flora: Common Rock-rose occurs extensively as an underlying carpet, and there are drifts of Horseshoe Vetch, Chalk Milkwort, Cowslip and, less prominently, Bird's-foot Trefoil and Wild Thyme. Kidney Vetch occurs in gaps in the sward, becoming numerous in places after a hot summer in which grass growth has been checked. Buried in the grass litter is much Hairy Violet. All these, bar the Milkwort, are butterfly larval foodplants. There are also many butterfly nectar plants, particularly scabiouses and knapweeds, though Marjoram, a favourite nectar source on southern chalk downs, is scarce here and in the Cotswolds generally. The slopes of Rodborough turn yellow with Cowslip, vetch and rock-rose flowers in May, then pink with thyme and orchids in June, before the fading grasses take over in late summer, and the flanks take on a straw-like hue.
This flora enables a wide range of downland butterflies to occur. In early spring Green Hairstreaks are numerous, appearing sometimes as early as late March. The Duke of Burgundy has several colonies along the foot of Rodborough's steep east- and west-facing flanks – usually three sizeable colonies and three or four tiny, satellite colonies, but much depends on the vagaries of spring weather. His Grace moves around a fair bit on Rodborough, for butterflies can freely wander there. Dingy Skippers are numerous, but the Grizzled Skipper is all but absent, as is its main foodplant, Wild Strawberry. Brown Argus and Small Blue are ubiquitous both here and elsewhere on the Cotswold grasslands. Marbled Whites and Ringlets abound from mid-June through to late July, when they suddenly finish. The Dark Green Fritillary has occasional years of plenty, but is sometimes seen only singly. Several spots along the slopes support colonies of the Chalkhill Blue, which usually appear around July 25th and linger on into September. These colonies ebb and flow acutely, for no obvious reason. The sward is too dense and coarse for Grayling and Silver-spotted Skipper, though both occurred in the not-distant past, when the slopes were well grazed by Rabbits. In the early 2000s the Adonis Blue mysteriously, perhaps miraculously, reappeared, after an absence of some fifty years, and has established some impressive colonies along the slopes. Bainbrigge Fletcher's records indicate that the Large Blue occurred on Rodborough Common during the 1890s.
The commons are used extensively for recreation, being the green lung of the ribbon-like development in the Stroud valleys, though there are many secret, unfrequented spots, mainly at the foot of precipitous slopes. Rodborough Common boasts its own ice-cream factory, Winstones of Rodborough, which was established there in 1925 and is open almost every day of the year. On hot summer days it attracts, rightly, a veritable multitude, and also sends ice-cream vans onto various other parts of the commons. Winstones is a glorious ice-cream empire, and a fundamental part of the spirit of the Stroud commons. Kite flying is prominent on windy days on the commons, and Minchinhampton Common boasts the country's first organic golf course. Of course, dog walking is now pre-emptory, especially on Rodborough where it is a 24/7/365 activity. Dog walkers almost exclusively confine themselves to the slope tops there, not least for the panoramic views – across the Severn to the Forest of Dean and the Welsh hills blueing in the distance. Occasionally a ball bounces down towards a lone naturalist out butterflying on the lower slopes, followed by a panting dog. The slope bottoms are littered with lost balls, Frisbees and the like. Each Christmas, a group of dog walkers decorates a prominent Hawthorn tree on the slope top, with tinsel and baubles and Christmas cards from their dogs – to the place. This act exemplifies the extent to which the commons are deeply loved and revered. The commons also host an interesting night life, but that may best be left to the imagination. At midnight on New Year's Eve, however, one can look down from the heights of Rodborough onto spectacular firework displays erupting from the surrounding valleys. Without doubt, Rodborough, with its Skylarks and Meadow Pipits, offers interesting and unique experiences. It is a quintessential part of the Cotswold experience, as integral as the poet Laurie Lee's heartland, which lies a few kilometres to the north at Slad.
Some 5 kilometres eastwards up the Frome valley from Rodborough nestles a hidden side combe, known locally as Strawberry Banks, below the perched village of Oakridge. Surrounded by dense and ancient Beech woodland, the Banks consist of a few acres of SSSI limestone grassland on a west-facing slope. This is a world apart, a place of pensive mood unpenetrated by traffic noise, where a rushing stream hidden in the combe bottom murmurs melodically to all who would listen, where bird song resonates wondrously, and where meditative Buzzards drift slowly overhead. The Banks are in the stewardship of the Short family, who understand the place profoundly, truly belonging there, and run the 4 hectares (10 acres) as a nature reserve in partnership with the Gloucestershire Wildlife Trust. In consequence, Strawberry Banks is a most contented place. The flora is rich, containing Lesser Butterfly-orchids, much Dyer's Greenweed and drifts of Kidney Vetch, though some classic downland plants are absent, notably Common Rock-rose and Horseshoe Vetch – together with their associated butterflies. The deeper soils, on the lower reaches of what by Cotswold standard is only a modest slope, support swathes of Devil's-bit Scabious. In September, these lower slopes haze over with the purple flowers of this plant. The butterflies of early autumn home in here, to feed up prior to hibernation. Brimstones then overwinter in Ivy tangles on the nearby Beech trunks, Peacocks in hollow trees, and Commas amongs
t the Beech leaf litter.
This is the heartland of the Marsh Fritillary, the only place in the Cotswolds where this rare butterfly maintains a permanent – or rather, long-term – population. During sequences of poor springs and wet summers the population plunges – as low as 52 individual larvae recently. Occasionally, when Gloucestershire's neurotic spring climate actually allows a series of clement springs, the butterfly sallies forth to colonise other slopes in the vicinity, sometimes reaching as far as Rodborough Common. During the remarkable Marsh Fritillary expansion phase of 1982–1985 the butterfly colonised much of the southern Cotswolds, reaching as far as Painswick and the southern flanks of Cheltenham, to the north-west and north. Dingy Skipper and Small Blue also occur in good numbers on Strawberry Banks, Green Hairstreak breeds merrily on Dyer's Greenweed and hangs about on Hawthorn and Crab Apple blossom, and during high summer Marbled White and Ringlet abound, along with modest numbers of Dark Green Fritillary. Formerly, a tiny colony of the Duke of Burgundy existed, but it was lost when the all-important Cowslips succumbed to drought during hot summers in the mid-1990s. The Banks are grazed in autumn, usually by ponies but occasionally by cattle. Here, at last, is a place at peace with itself.
Head eastwards, up and out of the Frome valley, through sleepy Sapperton, and just before Cirencester (Roman Corinium) stands the dark mass of Cirencester Park Woods, some 805 hectares (2000 acres) of silvicultural woodland on terrain that has been wooded for centuries. The woods lie on land that rises gently from Hailey Wood, by the village of Coates in the south, through Oakley Wood in the centre, to Overley Wood at the north end. The woods are part of a vast estate that has been in the ownership of the Bathurst family since 1715. They have a varied history. The old medieval coppices are no longer traceable but the embankments of a medieval deer park are still prominent, as are the broad straight rides and intersections of a designed landscape laid out in 1718 under the direction of the poet Alexander Pope. There is a long tradition of silviculture here, for the woods are renowned for having hosted early experiments with continental varieties of Beech. Consequently, the woods are not SSSI. The late Earl Bathurst was a champion of twentieth-century silviculture, and introduced a number of conifer species to the estate – the usual motley crew of Corsican Pine, hybrid larch, Norway Spruce and Western Red Cedar. Until he died, in 2011, the woods were intensively managed: almost every year two or three blocks of mature trees, 1–3 hectares in size, were felled, and the land replanted with a mix of trees – conifers or conifer and broad-leaved mixes in the main, though fellings of old Beech and Pedunculate Oak were by and large replanted with those species. Young plantations were assiduously weeded, and herbicide was often sprayed between rows of young trees to control brambles and coarse grasses. The estate is not without its idiosyncrasies: public access is permitted on foot and horseback, from 8 am to 5 pm, but cycles and dogs are prohibited. Dog walkers are, of course, steadily penetrating the woods. The woods are not shot but are hunted, vigorously, often by Royalty, who also frequent the polo grounds that lie to the immediate east of Oakley Wood.
Cirencester Park Woods are the last stronghold of the Pearl-bordered Fritillary in Gloucestershire – for the butterfly is deemed extinct in the vast Forest of Dean, across the River Severn. Here the butterfly has survived, and at times thrived, utilising the uninterrupted supply of clearings and young plantations produced by forestry operations. It has followed the commercial woodcutter from place to place, as always was its wont in woods. Some fifty colonies have been formed since an in-depth study began in 1992. However, by no means all felling operations have produced suitable Pearl-bordered Fritillary habitat; indeed, only about a third have. Sometimes the butterfly moved straight in, but quite often it waited until a secondary forestry operation took place – such as cutting or spraying brambles. The activities of a large Fallow Deer population extended the longevity of several colonies, by slowing down or even destroying saplings – until a vigorous deer culling programme commenced during the late 1990s. Many clearings failed to come good and produce the necessary violets, because felling and extraction took place during wet weather, or simply because the ground got covered by coarse grasses in wet springs and strong grass growth seasons. By far the best habitat appeared during dry springs, in which violets were not out-competed by rampant Wood False Brome or Tufted Hair-grass.
Following the Pearl-bordered Fritillary in these woods is not easy, partly on account of the sheer scale of the woods, but also because colonies continually shift, appearing and disappearing with surprising alacrity. Many colonies persist only for a year or two, the longest for thirteen. Often, a clearing was occupied initially, for a short while, before the colony died out, only for the butterfly to reappear there a few years later, after a secondary phase of management. The butterfly is very much under the thumb of spring weather in these woods (the district is plagued by convective cloud during spring and, being on the western side of Britain, is prone to lingering weather fronts). Curiously, the climate at the lower, southern end of the wood is sunnier and drier: consequently the butterfly often appears there a good week earlier than at the higher, cloudier northern end. In flight seasons dominated by poor weather, the butterflies are loath to cross from an ageing habitat patch on one side of the ride to new habitat on the other side, yet in hot weather they become highly mobile and wander throughout the woods, and even beyond.
The soils in Cirencester Park Woods are probably too fast-draining for the Small Pearl-bordered Fritillary, which was never a Cotswold butterfly anyway, though colonies of Dark Green Fritillary form periodically in some of the larger clearings. Silver-washed Fritillary occurs in modest numbers around the surviving areas of mature broad-leaved woodland, though much of its former breeding areas have been felled – and have become, at least pro tempore, Pearl-bordered Fritillary habitat. The White Admiral is all but absent – as its larval foodplant, Honeysuckle, is rare due to browsing by Fallow Deer. In spring, colonies of Grizzled Skipper occur in some of the young plantations, notably where its favoured foodplant, Wild Strawberry, grows. The Duke of Burgundy has the vaguest of presences in the woods, breeding apparently on Primrose, but disappearing for years before suddenly reappearing. The broad grassy rides support good populations of the commoner grass-feeding butterflies, though they have been mown every late summer and are often heavily poached by horses.
Above all, Cirencester Park Woods have a unique feel about them. Overley is far and distant, Oakley is haughty and aristocratic, and Hailey is ethereal and poetic. The woods are not remotely like Forestry Commission woods, despite the presence of acres and acres of ranks of sombre conifers. For a start, the conifers are well maintained, as the estate foresters regularly thin out the timber stands. The main difficulty here is that the forestry that has been practised here for the last few decades is not sustainable, let alone cost-effective. Furthermore, the supply of mature broad-leaved woodland for felling is dwindling, and the estate is moving over from plantation forestry to what is called continuous-cover forestry. In butterfly terms, that is good news for the Silver-washed Fritillary but bad news for the Pearl-bordered Fritillary. To date, the latter has survived, and often thrived, on the back of commercial forestry; but from now on it will require positive conservation measures if it is to remain not just in Cirencester Park Woods but in the entire county of Gloucestershire.
Of course, there are many other rich butterfly localities in the southern Cotswolds, but the above are the ones to which I became hefted, and where I carried out long-term studies. But please do not think that the Cotswolds are a butterfly paradise. Several species have become extinct there, though the Large Blue is being reintroduced and the Adonis Blue successfully reintroduced itself. Moreover, butterflies and butterflying are somewhat handicapped by the region's climate, which is cooler, cloudier and wetter than much of the rest of southern England, especially in spring and early summer. There are, though, elements of the rural idyll so brilliantly eulogised by Laurie Lee in Cider with Ro
sie, and in his poetry.
All are but parts of one stupendous whole,
Whose body Nature is, and God the soul.
Alexander Pope, 1734
25 Of Iris and Adonis
In a dataset that goes back to the 1650s, 2006 went down in history as England's warmest year on record. It brought the warmest June since the long hot summer of 1976, the hottest and sunniest July and the mildest autumn on record. Climate-change thinking was to the fore, for this was the year when so-called ‘global warming’ hit the UK, at least as a mindset. Yet despite widespread hose-pipe bans it was not an especially dry year, but one that began with groundwater levels very low after a dry winter. A wet second half of May restored river levels, there were frequent if localised thunderstorms during the summer, August was indifferent, and the autumn eventually became extremely wet.
Good summers quite often come in on the back of a late spring. March 2006 was cold and at times bitter, with a wet ending. There were few opportunities for butterflies to fly. April dried things up, but was dominated by northerly airstreams, which brought cold nights. At the end of April the dandelions were only just at peak and the oaks merely starting to leaf. In effect, this was a slow, late spring – the sort good summers prefer. The Duke of Burgundy only started to emerge at the turn of April – I saw Noar Hill's first of the year on the 30th, and the first at Rodborough Common the following day, May Day. Pearl-bordered Fritillary was even later, only beginning its flight season on May 4th near Buckfastleigh on the southern slopes of Dartmoor, where it usually starts to emerge about April 20th. The first individuals were seen in Cirencester Park Woods on May 11th, but the butterfly invariably appears a good week later in Gloucestershire than in warm south Devon.
In Pursuit of Butterflies Page 34