Thursday 16 May 2019

Pearls and Burgundy 13th May 2019

Monday brought the promise of all day sunshine and my thoughts turned to Sussex and butterflies. Now is the time that two favourite butterflies of mine fly and I had two locations in mind where I would go to look for them;  Kithurst Hill near Storrington for the tiny but beautiful Duke of Burgundy and Rewell Wood near Arundel for the larger but just as desirable and equally scarce Pearl bordered Fritillary.

Like many of our butterflies both are endangered and require intense habitat management on special reserves to keep them from dying out. Such a shame it has to be like this but that is the way of it these days as land management methods become ever more incompatible and hostile towards the natural world.

My first stop was at Kithurst Hill which lies at the top of the West Sussex South Downs and where the South Downs Way crosses from east to west.  Kithurst Hill is a north facing slope looking over the Sussex Weald towards the distant haze blue bulk of the North Downs.

A slightly chilly southerly wind was blowing at the top but by walking down the cowslip festooned slope it became warmer  at the bottom, a sun trap, sheltered as it was from the wind

The bottom of the bank on Kithurst Hill

Cowslips - the Duke of Burgundy's larval foodplant
It was almost noon and the heat from the sun had reached a sufficient intensity to persuade the butterflies that inhabit here to commence flying. A couple of Dingy Skippers were first to appear, and never does a butterfly live up to its name as does this one! Unremarkable and drab beyond measure these butterflies still retain an elusive charm as they whirr around on wings that move so fast they are a blur. They settled on the hard spherical heads of Salad Burnet, with their wings spread to absorb the sun but they have a curious habit of then slowly partially retracting their forewings  over their hind wings so the butterfly takes on a triangular form. I thought this hitherto un-noticed characteristic might just  have been  an isolated occurence with one particular individual but all the others I observed performed this curious movement too, once they had settled. 

Dingy Skipper
I have seen many Duke of Burgundys, so should not be surprised at how small they are, but I confess to always being taken aback each year as I first see their tiny dark brown forms scudding low across the downland grasses covering the warm chalky earth. Two males spiralling in combat were the first  I saw but they soon separated, each to settle, apart, in the sun, their dark brown wings chequered with amber markings and their underwings showing exquisite asymmetrical panels of white.

Duke of Burgundy
A miniature masterpiece that will be alive for a few days and then die. How can it be that something so beautiful has such a very brief existence in this the last and most attractive stage of its life? I found another individual crawling amongst some primrose leaves, the larval food plant, delving deep into the dark recesses at the coswslip's base. It was a female, its abdomen distended and bulging with eggs which it was laying as quickly as possible. No time to lose in her brief existence. She bent her abdomen under a selected primrose leaf and deftly deposited an egg on the underside of the leaf. Very precise and particular before moving on to another leaf to repeat the process.

Duke or should I say Duchess of Burgundy laying eggs
She flew and I lost sight of her against the slope but a fellow enthusiast found a pair mating, the two insects hanging from a grass blade in union. Nothing would part them and for well over half an hour they consumated their liason, moving regularly along blades of grass and even falling onto the ground at one stage but never for an instant did their two conjoined bodies separate. I became anxious for them as they lay on the ground.

Mating Duke and Duchess of Burgundy

They could easily be trampled by someone wandering around unaware of their presence, so small and inconspicuous were they in the grass. I placed my finger under one of them which promptly walked onto it  bringing the other butterfly with it. I transferred them onto a blade of grass growing on the mound of an ant hill where they would be safer from unwary feet.

More enthusiasts began to arrive, not many but enough to persuade me to go and seek a quieter area and find some Dukes all to myself. I walked back a short way down the approach lane and on the high banks on either side, again full of cowslips, I found a freshly emerged Duke and sat in the sun admiring its perfection, and then I found another.The secret is to just wait and eventually they will fly and reveal themselves, being usually a male patrolling its small territory.

There were of course other butterflies here, diminutive Brown Argus their wings outlined in orange spots, Common Blues, an indescribable shade of blue in the bright sunshine, large citrus yellow Brimstones looking huge to my eyes after peering at the smaller butterflies and finally a Green Hairstreak,  an emerald triangle of closed wings angled to the sun, sat enthroned on a hazel leaf in a  secluded corner by the car park.

Brown Argus

Common Blue

Green Hairstreak
It was now mid afternoon and time for me to head to my second destination, Rewell Wood and hopefully renew my acquaintance with the Pearl bordered Fritillarys whose habitat management there is being supervised by Neil Hume of Sussex Butterfly Conservation and  which requires a three year rotational coppicing, courtesy of a lot of hard work during the winter months by volunteers and  the permission of the Duke of Arundel who owns the commercially harvested wood.

Part of Rewell wood that has been coppiced in readiness for
next year, 2020

The coppiced habitat frequented this year by the fritillarys

Commercial forestry operations
It had become a glorious afternoon of sunshine and parking the car in the tiny layby off the busy A27 I walked the access track through the wood to where it joined the wide ride crossing it and along which are the three coppiced areas that provide a home to the Pearl Bordered Fritillarys. The western and middle thirds were where I saw them last year but when I met Neil Hume last year he told me that this year the butterflies would be in the eastern third as this would be the most suitable habitat for them..

Initially I saw little sign of any butterfly but then after no more than a minute a Pearl flew low over the bare ground past me, and then looking down onto an insignificant patch of blue purple Bugle which the Pearls love to nectar on,  there was another, half hidden,  its ginger wings covered in black spots and squiggles, nectaring deep at the base of the flower.

I walked on and a succession of Pearls came flying across the bare strip of ground I was on, or fluttering out from the coppiced trees further in. Others were basking in the sun or nectaring on the Bugle flowers. I was seeing dozens of Pearls, a veritable bonanza of this rare and threatened butterfly and this year they seemed inclined to remain in one spot for more than a few seconds.

The string of white pearls on the outer edge of the underwing from
whence the butterfly derives its name

This individual had three symmetrical white tips on each hindwing

Last year they were frustratingly and continually flying and not settling until late in the day. Neil  had told me they were males looking for females but this year there was not so much evidence of this continual quest for females

Pearl bordered Fritillarys
I did find one very tatty and presumably male Pearl harassing a perched female but she continually quivered her wings, the equivalent of a female Pearls brush off, so presumably she already had been mated or was not ready to mate yet. The male gave up and flew off.

The only other butterfly species I found were a couple of delightful Small Coppers which were in pristine condition and obviously hatched recently, possibly just today.

Small Copper
I walked the ride up and down on several occasions and was pleasantly surprised to have the place entirely to myself. I saw not another soul for the whole two hours I was there.

The gentle solitude of the wood, punctuated by a Garden Warbler's rich song and Blackbirds singing gently from deeper in the wood set the mood and it was with heart uplifted that I left Rewell Wood and Sussex in the early evening sunshine. 

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