We had been set two main target species, High Brown Fritillary and Duke of Burgundy. The former is not a beginner's butterfly, being hard at first to separate from the similar-looking and equally fast-flying Dark Green Fritillary, with which it almost invariably occurs. But I had already cut my teeth with this butterfly, both in the New Forest and up here, on the Morecambe Bay limestone hills. The latter species was easier, for I had developed a sound method of surveying for it – by searching for the near-diagnostic peppering and panelling holes that its larvae make in Cowslip leaves. We found huge colonies of High Brown Fritillary on several of the hills, north and south of the Kent estuary, and some just east of the M6 motorway. Whitbarrow proved to be a bastion of this magnificent fritillary. His Grace the Duke of Burgundy was more elusive, but south of the Kent we found small colonies on the summit of Arnside Knott, on nearby Heathwaite, at the delightful Fairy Steps near Beetham, in two places on Gait Barrows NNR, and at Heald Brow in Silverdale. North of the estuary we found colonies on Yewbarrow, the lonely hill above Witherslack, along Brigsteer Scar, and a massive colony above the hamlet of Howe on the east flank of Whitbarrow.
Our main finding was that the area was clearly of national importance for both High Brown Fritillary and Duke of Burgundy, and probably for some other butterfly species too – and that we needed to return the following summer for further surveys, for the job was only half done. One interesting finding was the discovery that the Northern Brown Argus bred on both Common Rockrose and the rare Hoary Rockrose, for we found numerous ova and many young larvae on the latter plant along the crag and scar system that runs north to south due west of Kendal. The expedition was so successful that we were promptly contracted to return the following year.
Returning south, this time without vehicular vicissitudes, I found that butterflies had enjoyed a July even hotter and, localised thunderstorms apart, drier than that of 1976, and were consequently profuse. The Brown Hairstreak began to emerge at Selborne at the beginning of August, producing a relatively strong brood, though days quickly became too hot for this lethargic butterfly, the males of which are active only until the day warms up properly, after when they tend to become comatose high up in Ash trees. The hot weather had ensured a large second brood of the Wall Brown, a plethora of Common Blues, and a scatter of rare second-brood specimens of the Dingy Skipper, an early-summer species which will produce a few August specimens in hot summers. The downs turned grey, as is their wont in drought summers, clay soils developed hexagonal cracks, and the few dry heaths that had not been incinerated in 1976 went up in flames (heaths that had burnt up in 1976 had not yet regrown into a combustible condition).
A sizeable home-grown brood of Clouded Yellows started to emerge, from about July 23rd, probably augmented by fresh arrivals from across the Channel. Like the Painted Lady, this insect is a fast breeder, which in hot weather can metamorphose from egg to adult in six or seven weeks. There were reports of a swarm of them in a Lucerne field near Radlett in Herts. Every south-facing downland slope in southern England was graced by half a dozen or more of these living jewels, the males ceaselessly patrolling in search of freshly emerged females. There were at least ten on Noar Hill on August 4th, and I even saw a male flying down Selborne High Street, right outside the Gilbert White & Oates Museum. The females were again seen laying eggs on tiny semi-isolated plants of Bird's-foot Trefoil and other vetches in hot bare-ground situations, such as along the south-facing sides of tractor ruts. Numbers peaked during the second week of August, but remained high throughout that wonderful month. I followed another generation of larvae through in the wild, on Noar Hill and at Broughton Down in west Hampshire. The tiny larvae lay along the mid-ribs of the trefoil leaves, but the larger ones tended to hide away amongst the foliage.
September commenced with a thunderstorm, which augured well, but then fell apart as a deep Atlantic gale came over on the 2nd, persisting for three days. Butterflies were decimated by this, and were then annihilated by cold weather coupled with pulses of heavy rain mid-month. Consequently, the second home-grown brood of Clouded Yellows all but failed, for only a few individuals were seen into the autumn. I saw my last on October 6th – a female busily laying eggs on clover leaves in the lawn of a garden near Alton. Warm sunny weather during October came too late, for the bad September had stopped the 1983 butterfly season in its tracks. But three ecstatic summer months, following on from a generally good season in 1982, had set butterflies up very nicely for 1984.
Arnside Knott
The clitter of footfalls,
softened on scree paths,
past sun-straw heads of
Blue Moor-grass that wave
the July breeze, and blow
From here to here alone;
for there is nowhere else
to journey, just this place
of warm grey-stone paths,
and clear intensity of light.
Estuarine sands, stretch
silvering into distanced haze
where mountains far off fade;
whilst here, on this lone hill,
the wind and trees are one.
13 Nineteen eighty-four and all that
To many naturalists New Year's Eve is a special time, not to be wasted singing Auld Lang Syne at parties. Naturalists want to be out and about, amongst the morass of dark trees, under the starlight, bidding adieu to the old and welcoming in the new; or saving their energies for a dawn raid or a day out somewhere special. To naturalists, New Year is all about promise, the promise of the coming year, and it has to be launched, properly. Welcoming in the New Year is therefore part of their spirituality, if not their religion, though non-naturalist spouses may struggle to understand this – and drag them off to parties. My spouse did understand. Thus, I saw 1984 in on Noar Hill, on a clear, mild and windy night, and felt the New Year roar in on a treetop wind that whisked away a mild December. A vicious gale arrived on January 2nd, from the north-west, blowing tiles off The Lodge roof and wrecking the nylon sleeve in which a few Purple Emperor larvae were hibernating. The Lodge liked shedding tiles. The Emperor was in decline in my life; it was almost as if he had cast me out, whilst the Duke of Burgundy and High Brown Fritillary were in ascendancy. Perhaps I had been placed out on loan, for development?
Winter was mild and forgettable. The more memorable parts of it were spent searching for White-letter Hairstreak eggs on the new generation of elms that was springing up. One wood, at Blacknest on the northern end of the East Hampshire Hangers, revealed eggs on three species of elm – English, Smooth-leaved and Wych Elm. Now that presented interesting opportunities for study.
Spring was in danger of bursting through too early, especially when the first day of March brought out the first butterflies of the year. I opened the season with a male Brimstone in the far chalk pit on Noar Hill, up against the beech hanger. However, the rest of March was cold and dull, and spring ended up running late.
April drifted in on a bitter northerly wind that carried spells of spring-like sunshine punctuated by snow showers borne by towering clouds, the temperature alternating accordingly. It was a memorable day, hinting that April meant business. At last the Chiffchaffs arrived, in April's second week, and the White-letter Hairstreak eggs I had marked out on elm twigs, using coloured pipe cleaners, began to hatch. The larvae quickly buried themselves into expanding leaf buds, or ageing flowers, and disappeared. The wind veered from north to south, and a truly wondrous April ensued. Spring caught up with itself, then rushed gleefully ahead with riotous abandon, such that each day, almost each hour, saw monumental change. Brimstones, Commas, Peacocks and Small Tortoiseshells were all out and about in unusually good numbers. Holly Blues appeared out of nowhere, as is their wont; the males wandered about incessantly from bush to bush, searching for freshly emerged females. At The Lodge, half a dozen males ceaselessly explored the contours of the laurel bushes, now with upright panicles of pale flowers that scented the air. The Cuckoos arrived. Each morning, at the flus
h of dawn, they would meet up in the giant Beech tree that towered above the house, noisily, for Cuckoos mate with gusto. After mating, and waking the inhabitants of The Lodge, they would fly off to feed in the nearby hop gardens.
In such conditions limits can be pushed, and butterflying is at its best when limits are being pushed. At Noar Hill, the first male Duke of Burgundy emerged on April 25th. At the time that sighting appeared to be the earliest the butterfly had been recorded anywhere in England since the amazing spring of 1893. That appearance, and the accompanying record, boded well, for I had just secured a useful grant from what was then the World Wildlife Fund (now the World Wide Fund for Nature) to study the ecology and conservation of the Duke of Burgundy. Of course, the wretched butterfly then emerged early, and caught me in Ethelred The Unready mode.
The fine April weather, on top of two good summers, was surely an omen of a third good summer to come. The previous two had been good, even very good, and butterfly populations had built up incrementally. I was back in the dizzy heights where I had wandered so joyously in the Long Hot Summer of 1976, only now there was work to be done – butterflies needed conserving.
At the end of a sunny and dry April Mrs O and I spent a memorable hour watching a huge female Large Tortoiseshell flying about high over a large stand of Smooth-leaved Elm in the hanger near Blacknest where I was studying White-letter Hairstreak larvae. Presumably, this giantess was seeking to lay eggs, though I failed to spot any of the gregarious larvae later. During the late 1970s and early 1980s this butterfly held some sort of exiguous existence along the Upper Greensand system of the East Hampshire Hangers, that sinuous band of scarp slope woodland that runs northwards from the South Downs near Butser Hill before eventually petering out into Alice Holt Forest. This butterfly was almost the size of an Empress, and behaved similarly, aloof and incompliant. She was, though, one of a kind that was supposed to be extinct in the country at the time. The half-dozen sightings in the hangers during that era suggested otherwise, for no one had released the butterfly there – no butterflyers even knew of the hangers.
Much of May was plagued by nagging convective cloud, the sort that develops quickly in the morning but dissipates at the end of the day to allow cool, clear nights. Butterflies had some flying time most days, but would have liked more. The month was all a-stutter.
I had experimented with mark-and-recapture work on Duke of Burgundies at Noar Hill during 1982 and 1983, having been taught by the likes of Jeremy Thomas and Keith Porter, scientists who between them had marked several thousand butterflies. This technique enables one to determine how long individual butterflies live, how far they move and, for sedentary butterflies like Duke of Burgundy, the population size. It is, though, rather addictive, and one can spend too much time marking new specimens and not enough time seeking recaptures.
Originally cellulose paint was used, but by 1984 quick-drying oil-based felt-tip pens were available. By placing two small dots on the wing undersides, one for tens and the other for digits, each butterfly is given its own unique number, by means of something called the clock method. The butterflies do not seem to mind, but one needs to handle them with care. Most of the male Burgundies I marked flew straight back to their chosen territories, resuming their never-ending hunt for receptive females, and fighting each other in the process. I had one minor accident, when a purple felt-tip leaked badly and covered one unfortunate male almost entirely: he lived for at least another ten days, twice the average lifespan of a male. Aged seven days, and still covered in purple, he was seen mating with a fresh female, and a particularly pretty wench she was at that. Out of a total sample of 348 males marked, the longest ‘life’ measured for a male was 22 days (marked when freshly emerged), with three others living for at least 20 days. Not bad for a thumbnail-sized insect.
Burgundy males are wonderfully territorial, simply because this is their way of finding mates. Males establish territories in sheltered spots which warm up early in the morning. There they perch, low down, flying up to intercept any small dark flying object that passes by, in anticipation of it being a virgin female. Green-veined Whites and Orange-tips are ignored. At Noar Hill, favoured territories at the foot of ancient chalk-pit banks are occupied annually, often by more than one male – which means that a lot of male infighting takes place. Most of the primary territories in use when I first saw the butterfly there in 1976 are still utilised today, though some have been lost to scrub invasion.
Mark-and-recapture work found that males tended to live their lives in their favoured territorial patch, only moving to a new patch when the wind increased or changed direction and their original locality became exposed – for this minuscule butterfly seriously hates wind. More recently, I have found that males change territory when disturbed by people, a lesson some over-ambitious butterfly photographers need to learn. At Noar Hill, males occupying the better (primary) territories were considerably more successful at finding mates than those in the lesser (secondary) territories. The record is four matings by one particularly fortunate male, whom I named Byron.
One fine day back in May 1982, I had watched one particular male for six and a half hours. For 70 per cent of that time he was inactive, particularly from mid-afternoon, after the day's emergence of females had finished. But he did spend 46 minutes patrolling his tiny patch, a few square metres, and another 23 minutes intercepting 30 winged intruders. He squabbled with eight other Duke of Burgundy males, three Dingy Skippers, singletons of Small Copper, Small Heath and Wall Brown, and a number of flies. Best of all, he saw off a Willow Warbler that flew low overhead. He went to bed at 4.45, high up in a Hawthorn bush. I repeated this vigilance in 1984, with highly comparable results. However, about 10 per cent of Burgundy males behave differently, being almost nomadic. One male was recorded on six different territories on four different days over an area of a couple of hectares – positively peripatetic by Burgundian standards.
Burgundy females, by contrast, are at best highly uncooperative. One female followed continuously for more hours than I care to relate was comatose for 80 per cent of the time. Her longest period of inactivity lasted 53 minutes. She took twelve flights, totalling some 30 minutes. She had three sessions feeding from flowers and five sessions, totalling a mere eleven minutes, indulging in the all-important act of laying eggs, depositing seven. She was then lost, just before 4 pm, when she suddenly took off after a lengthy period of quiescence, and disappeared over a block of scrub. Other ‘stalkings’ of individual Duchesses were less successful, for these females have the habit of suddenly making off at fair speed after sitting around doing precisely nothing for lengthy periods. This is quite normal for female butterflies generally, who tend to follow a behaviour pattern of bask – fly – feed – bask – fly – lay eggs, etc. In 1984, I marked 89 females on Noar Hill, but recaptured a mere seven. Five of the seven had travelled more than 250 metres, suggesting that the females are considerably more prone to disperse than their male counterparts.
Suffice to say that I could not possibly follow butterflies like this had I not spent a fair proportion of my youth fishing. That taught me patience, and watching a butterfly is rather akin to watching a fishing float. Also, I am particularly grateful to the Test Match Special commentary team for maintaining my sanity during these incredibly intense and demanding vigils. In 1984 the West Indies were over here, and at the very pinnacle of their might, with the most fearsome battery of fast bowlers ever assembled – today's health and safety standards would have prevented them from playing.
At the end of May, after a wet Whitsun bank holiday, I entrained for Silverdale on the Cumbria/Lancashire border, and spent four vernal days studying Duke of Burgundies and their friends and relations at Gait Barrows NNR and at Heathwaite, by Arnside Knott. May 1984 had been good in that district, far better than down south, and butterflies were in superb numbers. Spring in Silverdale is something special, for there is an intensity of light in that region of low Carboniferous Limestone hills that is unique wit
hin the UK and is at its lucid best in late spring. Some day a vibrant artists’ community will develop there, and change the world of Art for ever. Deep poetry also lies there, undiscovered. Sure, Edward Thomas visited and wrote one of his poems there, but someday a great poet will dwell there, whose writings will change the world of Poetry for ever.
Gait Barrows became a National Nature Reserve after NCC compulsorily purchased it to prevent further quarrying of the limestone pavement. The damaged pavement areas soon became good for butterflies, and the reserve was colonised by the Duke of Burgundy in the early or mid-1970s. I was asked to solve the riddle of why it was there at all, as Cowslips and Primroses, on which the larvae feed, were decidedly localised, and also to advise on its conservation. But this is the most tenacious of our butterflies, capable of subsisting at low population level on just a scatter of suitable foodplants. A thorough search in sublime weather on May 30th revealed thirteen individual Burgundies, a reasonable tally, and a total of 83 eggs, 66 of which were in two small areas of scrub that had been coppiced two winters back. Fifty-seven of these eggs were on Cowslip, twenty-two on Primrose, and four on the ‘False Oxslip’ hybrid. We learnt that coppicing and widening rides in areas where primulas were growing under trees could really help this little butterfly, but the primula-rich areas had to be located first. Suffice to say that since 1984 the Duke of Burgundy has slowly but surely improved its status at Gait Barrows.
In Pursuit of Butterflies Page 15