Thursday 17 May 2018

A String of Pearls in Sussex 15th May 2018

Pearl bordered Fritillarys are the earliest of the British fritillary butterflies  to appear, often on the wing in April in warm Springs but emerging later, in May, if it is cold.Their lives are short, maybe a week. Sadly they now form part of a familiar tale in that they have been declining rapidly due to changes in forestry practices since the 1950's, when the emphasis changed to growing mature trees and only felling them after sixty to seventy years, which meant that the successional open areas of clearfell that this butterfly requires were no longer available. Today its best chance of survival is by careful management of its habitat on nature reserves or where sympathetic landowners make allowance for its very specialised habitat to be maintained. One example of the latter is Rewell Wood, near Arundel in West Sussex, part of the Duke of Norfolk's estate.

Last week Peter and myself, based on reports and photos of some Pearl bordered Fritillarys being seen well at Rewell Wood, made the long trip there in search of this rare butterfly. Peter had already been the previous week but failed to find anything but was not sure he was in the right place. Rewell Wood lies between two busy roads, the A29 and the A27. It is an extensive wood, comprised of coppiced hazel, beech, sycamore and conifer and some timber from the woodland is cut commercially. On our first visit we parked at Fairmile Bottom by the A29  but not having done our research thoroughly did not realise that Fairmile Bottom was itself an SSSI and LNR and was not really part of Rewell Wood but led up to it through an impressive and very steep unimproved calcareous downland slope and thence through some ancient Yew woodland. When we got to the top of the extremely steep scarp slope we found an extensive area of cleared ground beyond the Yews, full of Bugle, a favourite nectaring plant of the Pearl bordered Fritillary but after two hours of intensive searching and forlornly wandering various tracks we saw no fritillarys at all and in the end had to give up, defeated. Had we but known it we were reasonably close to the right place to see the fritillaries but our failure to get prior detailed information led to an ultimately very frustrating and unrewarding day.

We could blame no one but ourselves and vowed to do more research and then return. Today, armed with maps and a newfound optimism we set off for my second attempt and Peter's third, to see the Pearl bordered Fritillaries at Rewell Wood. We had worked out that our last approach had been from the wrong side i.e north, off the A29 and we should have walked further south once through Fairmile Bottom SSSI and LNR. Our subsequent research revealed that Rewell Wood could also be accessed from a tiny turning off the busy A27 on the opposite, south side, which would save a long walk.

So at 8.30am on a wonderful sunny Spring morning we set off from Peter's house in Garsington, negotiating the tail end of the rush hour traffic around Oxford and then made good time to the junction of the A34 and M3. This time, instead of taking the Motorway, we diverted across country, going via Petersfield in Hampshire and Midhurst in West Sussex to avoid any potential bottlenecks around Chichester. This resulted in what turned out to be a very enjoyable rural idyll as we drove down long and empty roads, made into corridors of green and dappled sunlight by the overhanging trees, every so often emerging into those hidden gems of Sussex villages that nestle in the bosomy folds of the South Downs.

We turned, after two hours, onto the busy eastbound dual carriageway of the A27  and drove along searching for the small turning we had read about. We came to a turning, the only one, signed Rewell Wood but it had prominent notices saying 'No Parking'. We were confused, was this the turning on the map or not? I was pretty certain it was but Peter was not so sure and as he was driving we carried on and at the next right turning we doubled back up the opposite westbound dual carriageway and parked in a nearby road.We then walked back down the original carriageway, risking life and limb as cars and lorries hurtled past within feet of us, to where an entrance to a bridleway was shown on Peter's map.

We found the bridleway and turned into the wood with relief, to follow the bridleway upwards into the shade and cool embrace of the wood and away from the intrusive  roar of  traffic. As we progressed the trees muffled the sound of traffic completely and we found ourselves walking in the soothing quiet of mature trees on a ridge above some mediaeval earthworks that are designated as an Ancient Monument. A Jay hopped upwards from branch to branch of a tree by the track and disappeared silently, a fleeting image of pink, black and white with a flash of blue. We came to a right turn on the bridleway and there, up and along, just a short distance away was clear blue sky and the obvious edge of the woodland.This looked promising.

We walked into sunshine as the bridleway opened out onto a wide ride with trees on our right and an area of rough open ground, formed by recently clearfelled trees on our left. We were to learn later that this ride, extending for about a mile has been specially prepared to provide the ideal habitat for Pearl bordered Fritillarys with a successional rotation of clearfell areas based on a three year cycle, so as one area becomes unsuitable, the fritillaries move to the next one along and so on. 

Views of the area and ride specially created by clearfell for
the Pearl bordered Fritillary
As we proceeded down the ride, the habitat looked ever more promising. The short grass was randomly peppered with the purple blue spikes of Bugle but we initially saw nothing to excite us.We walked along further and came to a narrow track running off into the woods to our left, after the first area of prepared clearfell, and, where the ride continued, there was a continuation of the grass bank but with a profusion of Bugle, showing blue through a tangle of low growing vegetation, mainly, dead bracken and bramble. 

A patch of Bugle some of which is pink rather than blue
Peter examined the Bugle closely and a minute later exclaimed 'I've got one!' He certainly had and there below us, nectaring on a spike of Bugle flowers was our first Pearl bordered Fritillary. We were in the right area at last. This rare, orange and black, woodland butterfly with its seven white pearls at the edge of its hind underwing had finally given itself up to us. It was high fives between us and then we attempted some photos which was not easy with the butterfly low in the grass, partly shaded and almost constantly moving position. Eventually it flew and we stood, somewhat at a loss, but then two more arrived, only to flutter at some speed across the ground and never settle, and so it went on for some minutes before they too disappeared. At the time we did not appreciate how lucky we had been to actually find a fritillary that was settled at this middle part of the day, if only briefly.

Pearl bordered Fritillary nectaring on Bugle

During the fritillary's absences I watched some Dark edged Bee Flies, a new species for me, gently probing the flowers of the Bugle. They nearly always remain almost at ground level, moving methodically from one flower to the next, their long, black, rigid proboscis extended like a lance in front of them, moving towards and then back from each flower as they inserted and retracted the nectar seeking proboscis. Charming little things, their tiny bodies encased in a brown fuzz, diffident and unassuming, as they went about their business. They seemed particularly abundant in the clearfell areas.

Dark edged Bee Fly
We split up, looking for more fritillarys and saw a reasonable number but they too never ceased flying but just moved around at speed and were surprisingly hard to follow as they flew just inches above the ground, often hidden by the low growing vegetation, which usually resulted in us losing track of them.

Eventually we settled to staking out a small and particular area that had been felled and cleared and was now regenerating but currently was still relatively bare with a warm dry leaf litter, a favourite of the Pearl bordered Fritillarys. We learnt later that this was an ideal area for the females to hide in and lay their eggs on the larvae's foodplant, violets, which also prefer this habitat. Consequently this area proved very attractive to males looking for females, hence the good numbers of fritillarys visiting it. We had plenty of sightings but not one settled as they continually cased the ground before flying onwards. I speculated that maybe all these were males looking for females but I am no expert.

So we stood in the sun, pleasingly warm, as a gentle breeze blew down the ride. It was  so good to be back in Sussex, my forever spiritual home and in such a beautiful secluded place, in my favourite county.

Thirty or so minutes passed by and two figures appeared, coming along the ride from the East. Unbeknown to us our luck was about to take a turn and very much for the better. One of the two was Neil Hulme, an ecologist who is or was the Sussex Project Officer for the wildlife charity Butterfly Conservation and is credited with saving the very rare Duke of Burgundy butterfly from extinction in Sussex. He has a remarkable history having changed career to work for Butterfly Conservation after spending thirty years in the oil industry. He has just completed a three year contract leading a project called Fritillarys for the Future which aims to conserve highly threatened fritillary butterflies in Sussex.

I can do no better than quote the words of Dr Dan Hoare, Butterfly Conservation's Head of Regions

..........Neil is a force of nature and his infectious enthusiasm, deep knowledge acquired through years of studying butterflies in the wild and passionate commitment to the hard work of nature conservation mark him out as a rarity  himself............'

He stopped to talk to us and what is so nice about Neil is there is no patronising or aloof attitude but just friendliness  and a willingness to impart as much information and advice as you can possibly want and answer any questions you may have. All achieved with humour, a smile and laugh. It is as if you have known him for years. I met him for the first and only previous time, when an ultra rare Queen of Spain Fritillary arrived near to Peacehaven in Sussex during September of last year and was similarly impressed by his willingness then to talk to anyone about butterflies.see here

Neil Hulme
He told us that our best chance to get a good photo of the Pearl Bordered Fritillary was after four o' clock when they would come down to sit and spread their wings, 'pancaking' as he called it, on a tree stump or leaf, absorbing the last of the sun's rays before going to roost. Other gems of information he imparted were that the fritillarys always roosted on the east side of a stump or whatever they chose as a roosting site as that is where the sun's rays would strike first in the morning. He suggested that rather than remain at Rewell Wood all afternoon we should go to Kithurst Hill until four or five o'clock, near the not very far away village of Storrington, where we could find Duke of Burgundy as well as Dingy Skipper and Green Hairstreak butterflies. In the meantime he also directed us to another area further along the ride that had also been clearfelled and where there were many Pearl bordered Fritillarys. We went to have a look and sure enough found a number of the fritillarys but like the earlier ones we had seen they were constantly on the move, forever restless.

As it was just gone one in the afternoon Peter and myself agreed to walk back to the car and drive to Kithurst Hill where we would rejoin Neil who also intended to go there. We walked back down through the wood, the sunlight and blue sky looking like a broken jigsaw overhead through the tree tops and the shadows of the leaves silhouetted like pieces of the same jigsaw on the pale dry earth.

We drove to a big roundabout above Arundel and stopped at a bikers cafe for a coffee.

A short drive later and after managing to miss the discreet turning to Kithurst Hill, we doubled back, found the turning and arrived, via a steep track, at the small car park on top of Kithurst Hill. Neil was already there, searching for Duke of Burgundy butterflies and we joined him on a downward slope full of cowslips, the 'Dukes' foodplant, and set about searching.

On Kithurst Hill
In a very short time we found a 'Duke' and then another two spiralling upwards, jousting with a Dingy Skipper. Further searching revealed a pair of 'Duke and Duchess' mating, poised on a leaf of a small birch tree at the base of the slope. Peter found a male Small Blue, newly hatched, a tiny gem of an insect, dull grey blue and almost impossible to follow as its tiny form flew low over the grass. A Green Hairstreak, our only one, put in a very brief appearance before flying off to the nearby bushes. The most abundant of the butterflies were the Dingy Skippers and I watched two spiralling round and round, just a couple of feet from the ground, for at least ten minutes before separating. The sunlit slopes with their mass of cowslips and fragile blue speedwell flowers were a joy to wander around. Orange Tips flew the woodland edges as did Common Blues, Brimstones and Large and Small Whites. I even found an adult Hairy Hawker dragonfly hanging vertically from a twig.

Hairy Hawker Dragonfly
It was heavenly, one of those days in Sussex that make me wonder why I ever left. Twenty five years have now passed but still the longing is there.

Mating 'Duke' and 'Duchess' of Burgundy

Duke of Burgundy

Dingy Skipper

Small Blue
It was four o' clock and we drove back to Rewell Wood as planned. Neil had told us that the small track off the A27 with the 'No Parking' sign was the right place to turn into after all, and so we did, parking in one of the only two parking places where you were allowed to leave a car. 

We went through a gate and walked past the neatly stacked logs of recently felled trees, the resin's  sharp fragrance from the cut logs hung on the air as we came to a tiny sawmill. Then, following the track onwards, we soon reached the same ride we had frequented this morning. Neil arrived at the same time and went off to survey a cleared area for Pearl Bordered Fritillarys while we sauntered up the ride to survey the small clearfell area where we had first stopped to view the fritillarys this morning. There was another couple of butterfly enthusiasts nearby but they were concentrating on another area and so we each kept to ourselves.

I stood silent and content as a Blackbird sang laconically behind me. Its notes and measured phrases given added resonance by the open woodland from whence it sang.

It was then a case of standing and waiting for the fritillarys to decide when they would cease their endless quests and settle to 'pancake' as Neil had put it. Sadly it did not quite work out that way as the fritillarys seemed intent on continually hurtling around and not stopping anywhere soon. Patience is a required necessity for folk such as us who indulge in seeking out butterflies, so I stood and waited, perfectly content and reflected that despite the fritillarys not settling I was seeing an awful lot of them and that in itself was no bad thing. Other insects were on the wing too or beginning to settle. An immature Broad bodied Chaser perched on a dead buddleia head and a Hornet cruised through the birch tops.

Broad bodied Chaser
Finally one fritillary did stop, almost at my feet, to nectar on a Bugle spike and we had our photo opportunity but you always want more. Time moved on and it was now five thirty and still the fritillarys flew on. A Garden Warbler was singing loudly and showing itself really well in some small birches as it competed with another male that was singing just as loudly from fifty metres or so up the ride. 

Garden Warbler

The other butterfly enthusiasts departed and it was now just us and the fritillarys. Neil joined us and we stood and waited for them to settle down. It did not happen but as the sun slowly lost its strength and shadows began creeping over the area of clearfell we were watching, Neil found a pair mating on a birch leaf still in the sun, just above our heads. It was now six thirty and he told us that this was one of the latest pairings he had ever witnessed. Probably the female had only hatched this afternoon.

Mating Pearl bordered Fritillarys
Then another fritillary came down to 'pancake' on a bed of moss on a tree stump. It had happened just as Neil said it would, albeit later than expected. In our conversations he told us that with the three year rotational cycle of clearance and habitat creation along the edge of the ride he estimated that this time next year there would be hundreds of Pearl bordered Fritillarys here. At the moment he estimated he had counted seventy three but probably because they were not all flying at the same time currently there were in the region of a couple of hundred in this specially created area. He also thought that quite a few had hatched this very afternoon as there were a lot more about than in the morning.

'Pancaking' Pearl bordered Fritillarys
We stood engrossed by the wealth of information we were being given and then another bonus came when we were shown a Green longhorned Moth. Not rare but an extraordinary creature with immensely long white, thread thin antennae and bronzy green wings..

Green longhorned Moth
By now we were looking for roosting Pearl bordered Fritillarys as it had come to that final part of a long day. Neil left us to go back along the ride to look for roosting fritillarys while we stayed put and watched as various fritillarys put down on the leaves of birches still in sunlight, spreading their wings to absorb the last of the sun but we could not find any that were roosting with closed wings.

The prize is to find one roosting, asleep with wings firmly shut, as then you can see the wonderful patterning on their underwings and the silver spotting that gives them their name.

It was approaching seven and I said to Peter  'Let's go. We have done really well and we have a long drive ahead of us but first we need to find Neil to say goodbye and thank you for making this day so very special for us.' Neil was just the other side of  some bushes and here was one final and possibly the best moment of the day for us. A last wonderful surprise. He had found a roosting female Pearl bordered Fritillary, stuck like a miniature flag to a dead plant spike some eighteen inches from the ground and yes, it was pointing east.

Roosting Pearl bordered Fritillary seen from both sides and behind
Note the kinks in one of its antennae!
We were overjoyed at this and what better way to end a truly extraordinary day with the butterflies of Sussex and with the not inconsiderable bonus of being in the company of one of the most knowledgeable and renowned butterfly experts in Britain.

Back in the car as we headed away from Sussex for Oxfordshire and home, the setting sun created pink fingers across the sky as if drawing the grey curtains of night down on an unforgettable day.

Oh Sussex, I miss you so.

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