Sunday 31 May 2020

A Bonanza of Glanville Fritillaries 29th May 2020

In May 2015 Peter and myself went to a nature reserve called Hutchinson's Bank, a steep sloping bank of chalk downland located near New Addington in the London Borough of Croydon. Our aim was to see a very rare butterfly called The Glanville Fritillary, named after its finder Eleanor Glanville.

They are only found here and on the Isle of Wight, so obviously Croydon was the easier option for us and setting off from Oxford in sunshine we were in good spirits but cloud moved in on the way and we were very fortunate to succeed in finding one Glanville Fritillary, for the brief period of time it showed itself in the cold, grey and unwelcoming conditions. As a butterflying experience it left us feeling somewhat unfulfilled.

I always resolved to go back to Hutchinson's Bank when the weather was more propitious and today, as with all the other days lately, was to be one of full sunshine and heat. A drive on pleasantly uncrowded roads due to the corona virus pandemic found me parking in Farleigh Dean Crescent and walking in on a bridleway to reach the reserve.

Hutchinson's Bank is 21.8 hectares in extent and is owned by Croydon Council but has been managed by London Wildlife Trust since 1987. It has recorded 36 species of butterfly and apart from the Glanville Fritillary, it is also home to a large population of the Small Blue, yet another endangered butterfly.

I set off along the bridleway at around ten in the morning, the sun even now very warm and the chalk on the bridleway baked hard from days of sun. So bright was the sun, the light was almost white, shimmering and casting great shadows from trees and bushes as it reflected from the chalk, the grass scorched brown by days of heat.

The Bridleway with the reserve on the right.I found four Glanvilles sunning themselves along this bridleway
I turned off the bridleway and passed through a gate into the reserve proper and almost immediately found a Dingy Skipper, flying no more than an inch from the ground, before settling to absorb the sun's warmth. Was ever a butterfly better named? An insect with wings that were an unremarkable shade of greyish brown, with a few paler markings on its forewings, it wins nothing in a glamour contest but in its own unassuming way it posseses an attraction, albeit only apparent to a butterfly enthusiast.

Dingy Skipper
I was unsure where the best place was to go and look for Glanvilles and even uncertain if they were out yet, but I found a warden who told me they were indeed flying and I needed to go back down the slope to 'the cutting' which was the best place to look for the fritillaries. He told me he had seen several flying around there earlier in the morning.

'The Cutting.' A Glanville Fritillary hotspot
I followed the directions and on turning into the cutting immediately recalled this was where Peter and I had stood five years ago waiting to see a Glanville. The chalk bank on one side of the cutting looked ideal for fritillaries, with a mass of Ribwort Plantain and Kidney Vetch growing there but of fritillaries there was no sign. However there were many Small Blues flitting about the Kidney Vetch, the foodplant of their larvae and on which they lay their eggs. 

This tiny butterfly, hardly as big as the nail on my little finger, was here in profusion, flying about and then settling to open their wings to the sun, rubbing them together, in a slow deliberate motion  as if savouring the warmth. They too are unspectacular, like the Dingy Skipper, the male with just a suffusion of violet blue on its steel grey upperwing surfaces where they join its body, the wings outlined with the thinnest of white margins. The female is dark brown with no trace of blue at all but when they close their wings both sexes show undersides that are the palest silvery blue with a row of dots across both wings like a string of black pearls.

I wandered the few hundred metres of the cutting and then walked back and as I did so a fast flying butterfly skimmed across the grass, worn in places down to bare chalk by the passing of numerous feet and then flew back past me at similar speed to settle on a patch of bare  chalk, and there was my first Glanville Fritillary, with wings spread wide to allow its furry body to absorb the heat that would provide the energy to power it through the coming day. 

This was a male, newly emerged judging by its pristine appearance, showing a pleasing base colour of rich brownish orange on its wings, overlaid with a patterning of symmetrical, wavy dark lines, the wings edged with white. Sheer perfection. It moved frequently but always maintained a presence within a restricted area of a few metres, often returning to the spot it had just left. Eventually it flew off and did not return.

I do not know quite why I am always taken  aback at how small all the springtime fritillary species are but it always comes as a bit of a surprise. Every year is the same. Maybe it's because I am so used to seeing the much bigger, bright orange Silver washed Fritillaries of high summer in my local woods in Oxfordshire but despite my mistaken perceptions the smaller fritillaries are always wonderfully enticing and attractive to look at.

I waited to see what would happen and another Glanville appeared and like its predecessor flew fast and low above the ground before landing on some dogwood but unlike the other, nectared frantically with wings outstretched. Slowly it began to close them and here was my opportunity to get an image of the  underwing which in all small fritillaries is a marvel of complex patterning, and in the case of the Glanville a mosaic of wavy orange and white bands profusely dotted with black on the lower underwing while the upper underwing is mainly pale orange with just a white triangle at its tip.

A male Glanville on a Dogwood flower
This too moved off and I sat and pondered on what to do next but eventually decided to remain where I was as it was far from unpleasant in this so called cutting that was now functioning as an effective suntrap.

In a little while, with no further sign of a Glanville, I decided to move on and asked the warden, who was working nearby, if there were any other good areas to look for Glanvilles. He suggested a couple and I headed off to investigate but having only taken a few steps encountered another Glanville flying to feed on the white flowers of dogwood growing at the top of the bank. That was three Glanvilles so far, just in this one particular location

I took some more photos, not that I needed any more. A man came by and asked me what I was photographing and I told him  and he moved on without saying another word. Strange I thought but I was to learn later, chatting to him, that this was Martin and he was well known here, eccentric and maybe even a bit of a celebrity and he came here every day. A true butterfly addict and widely knowledgeable on the butterflies of Hutchinson's Bank and indeed of butterflies in general. I learnt a lot from talking to him and he told me he normally voluntarily leads guided walks and does transects on the reserve and has even raised Glanville caterpillars in his home for release at the reserve. 

Following the warden's suggestions I found four more Glanvilles all sitting on the bridleway in the full sun and reluctant to move very far from where I had disturbed them, returning in a low fluttering flight to settle once more on the hot dusty track. I met Martin again, coming the other way and we compared notes on how many Glanvilles we had seen. My total was now up to seven as was Martin's.

I returned to the cutting to sit on a bench with Martin and we talked butterflies, comparing experiences from our respective parts of the country. Martin told me about the breeding programme at Hutchinson's Bank and of the respective fortunes of the Glanvilles here and on the Isle of Wight, their true stronghold. He recounted how he and others were trying to widen and strengthen the gene pool of Glanville Fritillaries to avoid inbreeding and subsequent extinction. He told me that the female Glanvilles would appear in the afternoon and showed me a tiny cage on the bank to protect the eggs of a Glanville which had been laid on the underside of a Ribwort Plantain leaf. 

Eggs of a Glanville Fritillary on Ribwort Plantain and on which the caterpillars will feed.
Martin told me they are due to emerge in a couple of days
He told me the females sometimes look paler, are larger, their fatter body does not extend as far as the bottom edge of the lower wings, unlike the male, and their wings are more rounded. I resolved to try and get a photo of a female as, so far, I had only seen males.The time passed easily and comfortably in the company of Martin as we talked and then he told me about a large almost bare area called  'the scrape' that contained a huge number of Small Blues. I enquired where it was and he said 'come with me' and we walked along the bridleway, then through a tiny wood and out into the sun and there, through a gate was a large area of sparsely vegetated chalk downland. 

The Scrape harbouring hundreds of Small Blues
It was, as he said, alive with Small Blues. They were everywhere and just by standing I was surrounded by their tiny forms, moving like specks amongst the short grass, settling on blades of grass and Kidney Vetch. They were hardly still for more than a few seconds, scrambling over flower heads, chasing after rivals or females or moving their bodies on the blades of grass to align them with the sun but then, discontented would move on, forever restless.Martin told me he had counted 1500 on a transect here last year. 

Yet another Glanville was sunning itself here and a male Brimstone was trying very hard to mate with an unreceptive female. I walked around the perimeter of this large square and found a Marbled White and Meadow Brown, both my first for this year. It was butterfly bliss and I made the most of it. Martin left to go for lunch but said he would be back later. He repeated that the afternoon was a good time to see the female Glanvilles which would come to lay their eggs on the Ribwort Plantain in the cutting.

A Glanville Fritillary perched on Salad Burnet
I in turn walked back to the cutting, feeling warm and content and now found there were other enthusiasts here but only  four or five. I sat on the bench and watched them finding their own Glanvilles but was happy to remain where I was content in the knowledge I had all the images I required. As I sat on the bench other Glanvilles arrived and departed, some settling in front of me on the warm chalk. A Red Admiral, a Small Tortoiseshell and a Holly Blue added to the day's tally of butterfly species but really, today, it was all about the Glanvilles.

Male Glanville Fritillary sunning itself on Ribwort Plantain
The other enthusiasts departed and it was just myself and one other that remained. I took another turn along the cutting, checking the sunny bank and another Glanville arrived but something was different about it, as it did not fly like the others but was fluttering amongst the grass searching but never seemingly satisfied. Eventually it settled and I took some images of it before it began fluttering once more, moving up the bank and out of view and out of reach. Could it be a female? I suspected it was and examined the images on my camera and its body did indeed not reach the edges of the hindwings and it was fatter in the body too. I was still unsure as it was not that much paler but certainly it was  larger than the males I had seen.

Female Glanville Fritillary on its foodplant Ribwort Plantain
Later, on Martin's return I showed him the images on my camera and he confirmed it was a female and cleared up the question of paleness by telling me newly emerged females are often nearly as bright as the males.

I decided to stay on a little while longer but did not see another female Glanville only, a few males  but I did find another couple of Dingy Skippers and a really smart looking Grizzled Skipper.

Grizzled Skipper
At 3.30 in the afternoon I called it a day having seen at least twenty Glanville Fritillaries although one would have been enough.

Who could possibly ask for more?

Butterflies seen

Glanville Fritillary
Small Blue
Common Blue
Holly Blue
Large Skipper
Dingy Skipper
Grizzled Skipper
Small Tortoiseshell
Red Admiral
Marbled White
Meadow Brown
Speckled Wood
Small Heath
Orange Tip

Friday 29 May 2020

Pearls in The Wyre Forest 27th May 2020

I arranged to meet Peter this morning at the end of a rural lane in Worcestershire that starts in some unexceptional housing and then descends in a series of steep winding curves to a small dusty area cut into a hillside that serves as a car park for the Wyre Forest NNR. Arriving a little early I stood by my car in the pleasant sunshine, in a place I had never visited before, but that was quite beautiful with huge oak trees towering over me and the land dropping away on one side into a narrow valley, the bottom of which contained an old mill house and the winding flow of Dowles Brook.

Wyre Forest is part of the largest area of ancient lowland, coppiced oak woodland left in England and the reserve comprises 549 hectares, a mosaic of grassland. meadows, old orchards and areas of scrub.

Even at 10am the car park was almost full but we managed to secure the last two spaces for each of our cars.  It obviously was a popular spot, with more and more cars arriving and as we walked into the reserve, following a wide pathway which used to be an old railway track, we and other pedestrians were constantly having to be aware of fast moving mountain bikers.

Not exactly a relaxing experience but we were soon to turn off the main pathway into another, quieter world that was far from the busy recreational thoroughfare we were currently walking along.

Our mission today was to find both Pearl Bordered and Small Pearl Bordered Fritillaries. Peter had been here last year so knew where to go, which were some tree enclosed meadows down by Dowles Brook, the meadows especially managed to enable both species of fritillary to thrive and prosper.

However, we had not gone far on the main pathway when we found our first Pearl bordered Fritillary, a very tatty and faded specimen that had only three wings but seemed little inconvenienced by such a handicap when it flew. Not a very satisfactory start but soon we found others, quite a few, that flew and settled while we followed and photographed them to our heart's content. It is always such a treat to see these rare and much desired butterflies, an innocent pleasure in a complicated world. 

A faded Pearl bordered Fritillary nearing the end of its flight period
A man passing by us stopped to ask what the butterfly was we were showing such an interest in. We told him it was a Pearl bordered Fritillary and in return he told us where there was a nest box occupied by a pair of Pied Flycatchers. He whispered enigmatically, 'Remember. Look for Box 33'. We thanked him and made a note to check out this information later but it was fritillaries first.

Pearl bordered Fritillary
Turning off the main pathway we entered an area of woodland scattered with numbered nest boxes for presumably Pied Flycatchers to nest in although some were occupied by Great and Blue Tits. Descending on a rough track into the valley bottom we came to the mill and crossed the brook. 

The Mill House
We eventually diverted into the specially maintained meadows for the fritillaries. There were meant to be both species here and after some delay we found our first Small Pearl bordered Fritillary flying fast and low over the grass but not willing to settle. Despite its orange colour it was surprisingly hard to follow as it flew erratically across the grass, to be lost in the distance.

Small Pearl bordered Fritillary
Soon we began to locate more fritillaries and it took some effort to differentiate the two but after a while we became relatively proficient as we encountered examples of each, fluttering around. Small Pearl bordered were, as their name would imply, noticeably smaller than their larger cousin and seemed much brighter, presumably because their flight season has only recently commenced in contrast to that of the Pearl bordered which is earlier and now, most of those we saw, were beginning to look faded. The underwing markings of the two species, when you could see them,  were diagnostic. This was by no means an easy task as the butterflies resolutely kept their wings open when they ceased flying and nectared on the various meadow flowers.

The easiest identifiable underwing differences, for me, were twofold. First the black spot in the centre of the lower underwing on the Small Pearl bordered was large and very obvious whereas the Pearl bordered had a much less definitive spot. Second, the row of seven white 'pearls', a line of markings towards the outer edge of the hindwing were outlined in black in the case of the Small Pearl bordered and orange in the case of the Pearl bordered.

Small Pearl bordered Fritillary showing a black dot in the cente of its hindwing and the seven white 
triangular pearls edged with black chevrons
Pearl bordered Fritillary showing a much reduced black dot on its underwing plus the seven white pearls are edged with orange chevrons

Small Pearl bordered Fritillary - above two images
Looking at the butterflies settled with open wings, Peter told me to look for 7-3-0 on the outer edge of the forewing of the Small Pearl bordered Fritillary. These are three marks that vaguely resemble the figures 7, 3 and zero.The markings are not the same on the Pearl bordered and as if this was not enough information to assimilate, the dark markings on the tip of the forewing of the Small Pearl bordered are usually joined whereas in the Pearl bordered they are not.

Small Pearl bordered FRitillary. The 7-3-0 feature is clearly shown on the left forewing as are the joined dots on the tip
of the same forewing
But enough of the technicalities and let us enjoy the fritillaries for what they are, beautiful insects which bring me much joy, that sense of enjoyment enhanced by the magnificent surroundings in which they were enacting their short lives on a wonderful early summer's day. We had the meadows entirely to ourselves for most of the time and made the most of it, walking through the lush grass and yellow buttercups, the steep slopes of the valley rising on either side of us and Dowles Brook bisecting the valley, sluggish from lack of rain but still chuckling and gurgling wherever rocks impeded its timeless progress below the green shade of the overhanging trees. Above us the sky was an unsullied forget-me-not blue.

Every so often we would see the burnt orange colour of a fritillary flying before us. the recently emerged Small Pearl bordered noticeably brighter than the Pearl bordered, now coming to the end of their flight season and with a faster more busy flight action. We followed them hoping one would settle but almost all were males, relentlessly patrolling, looking for a female to mate with. Occasionally one would settle and we tried to make the most of the opportunity but were often frustrated by the butterfly's ability to adopt positions not conducive to getting an aesthetic image that captured their essence and beauty. Countless were the times that a blade of grass interfered with the perfect image or cast a wayward shadow over the insect. We persevered and persistence got us the images we desired and in a way we enjoyed the challenge. Me, mainly wanting shots of the underwings, which in all fritillaries show a wonderful mosaic pattern while Peter was more desirous of an upperwing image.

Small Pearl bordered Fritillaries
The morning passed, unheeded by us, towards noon and we found in the far corner of our favoured meadow a fritillary hot spot. We had become aware it was better to stand and wait for the butterflies to come to us in this corner, rather than allow our enthusiasm to cause us to chase after them, often fruitlessly. 

So we stood patiently and were duly rewarded.

Small Pearl bordered Fritillaries
It was pleasant at the far end of the meadow. A place that was tucked away, hidden and secret from the regular passers by on the other side of the brook. There was a small drop to the brook below which  had formed a pool in the right angle caused by the bank jutting outwards. 

A fallen tree across the brook and some boulders were providing a temporary home for a family of Grey Wagtails, the adults chasing flies to bring to their fledged young, all the birds, adults and young constantly bouncing their hindparts and tail up and down. A curious movement, that in Grey Wagtails is accentuated by their long tail, the longest of any wagtail species in Britain.

Grey Wagtail - male
The unremarkable muddy bank of the brook, below where I stood, was suddenly transformed as a flash of bright blue betrayed the exotic and entirely unexpected presence of a Kingfisher which flew off up the brook to be followed shortly after by another. I moved my position to examine the bank more closely and sure enough there was the obvious entrance hole to their nest.

It was a true rural idyll and for a while I stood and forgot about the butterflies and embraced this moment of pure nature in a near perfect day. Mindfulness and Mother Nature inextricably entwined and working their magic once again on my soul. These are such strange times we are living through now, with every day seeming the same as the one before and the one after as our human world comes to a temporary hiatus, yet nature all around us, at this time of year, is never more energised and vital.

Mayflies were hatching and on wings of gossamer, shining in the sun, rose in slow spirals from the brook, fragile, ephemeral insects in the final stage of their life cycle, rising into the still sultry air only to be extinguished by a pair of Blackcaps, which had a nest nearby in a bramble clump and were taking full advantage of this bounty. Repeatedly the male and female Blackcap would fly out from the alders on the bank and seize the defenceless insects.

We walked back through the meadows, not an unpleasant experience in itself, the day now become hot and the shade bringing a welcome cooling greenness. Spring is almost over now and nature is at its most bountiful but the summer solstice will be here in three weeks and then it is a slow gentle decline from this profusion of growth and fecundity.

We took up the challenge from our earlier unknown passer by and went in search of the Pied Flycatchers and on a footpath skirting an area of sun dappled oak woodland reserved for birds found Nestbox 33 and its occupants, a pair of Pied Flycatchers feeding what appeared to be recently hatched young.The male was bringing all the food, tiny green caterpillars, and the female remained in the box for the most part, just looking out from the hole on one occasion.

Pied Flycatcher male at its nestbox
We left them and following the footpath eventually rejoined the main pathway with its attendant dog walkers, mountain bikers and families out to enjoy themselves. I felt a sense of loss at having left our secluded meadow and butterflies but we walked a half mile or so along the pathway but it was now hot and we were tired. An app. on my phone told me we had walked over four and a half miles so we called time and headed back to the car park, stopping to enjoy one last Small Pearl bordered Fritillary that was feeding on some bright yellow Horseshoe Vetch by the pathway.

At the car park I took some refreshment and then took out my bottle of 80% alcohol hand sanitizer. 'Cheers! ' came a voice from the car adjacent to mine as a man raised his bottle of sanitizer in acknowledgement.

These are 
indeed the strangest of times .

Tuesday 26 May 2020

Wood Whites in Northampton 24th May 2020

Butterflies possess a delicate and fragile beauty that makes them forever attractive. Combine this with the fact that they are, in the main, colourful and for the most part frequent unspoilt areas of habitat that are usually located in areas of great natural beauty and you can see why they prove irresistible to anyone with more than a passing interest in them.They somehow seem to recapture in our psyche an age of innocence, past times of childhood, imagined or not, that have long since vanished and the flash of colour when they open their wings cannot fail but to brighten the day.

Butterflies do not have personalities but each species is bestowed with its own behavioural characteristics that create the impression they do. Wood Whites are the smallest of our white butterflies and have a distinctive shape caused by their oval wings and long slim body. They have all white wings that show a faint shadow of grey on the undersides and both sexes possess a  smudge of black on their forewings. Wings which they only open in flight, as the minute they settle they are firmly closed. Small and creating an impression that they are as delicate as tissue they have a flight which is slow and hesitant, fluttering, almost constantly at ground level, through the stems and blades of grass.To fly a metre or so above the ground is, to a Wood White, the equivalent of taking a trip into the stratosphere and they forever dither along by the grass fringed tracks, the males looking for females to mate with, the females seeking out trefoils and vetches on which to lay their eggs.

Today, I went to meet Peter in a wood in Northamptonshire where we hoped to find Wood Whites which thrive here on a specially maintained habitat of grass verges, courtesy of The Forestry Commission.

Sadly our arrival coincided with the clouds rolling over, blown our way by a strong southwest wind. Hardly conducive to searching for butterflies. Nevertheless with the eternal optimism that is a pre requisite for any butterfly enthusiast in Britain's capricous weather we set off along the broad rides to find precisely nothing. You could hardly blame the butterflies which were no doubt hunkered down in the grass and vegetation, out of the wind and threatening rain.

Forty five minutes later after staring at countless blades of grass and flower buds, untroubled by sun, it began to rain and we sought shelter under the surrounding trees. For fifteen minutes it was very unpleasant as we stood and in my case getting increasingy chilled, wet and miserable. I had mistakenly worn shorts expecting sunshine but now the wind and rain whipped around my bare legs to add to my misery.

Looking to the heavens we could see further huge banks of ominous grey cloud but beyond was an expanding splash of blue, somewhere the sun was shining but would it come our way? We stood and waited as the blue patch with infinitesimal slowness edged towards us. Finally it was above us and with it came welcome sunshine. I felt the warmth on my skin and rejoiced as it looked like we were now in for a prolonged spell of sunny weather and our search for Wood Whites could recommence.

Expectantly we looked around for the butterflies taking to the wing but there was absolutely no sign of a butterfly apart from one Small White which disappeared into the forest.

Peter walked down a grass ride that was more sheltered from the wind and soon afterwards he hailed me with a shout that he had found a roosting Wood White, settled on a nettle leaf. 

Although complaining about the weather it had in fact, to an extent worked in our favour as it had made the butterflies lethargic and unresponsive, chilled by the cold and wind and now it would take them a little time to warm up and become active.

Wood White
We took the opportunity to photograph this oh so dainty insect as it clung to its leaf, apparently dead to the world. The warming sun soon persuaded another Wood White to take to the wing and it came on hesitant flight along the ride until it reached the roosting butterfly, whereupon it promptly landed right in front of it, head to head and the two communicated by regular rapid flicks of their wings, opening them for a fraction of a second then closing them. We presumed the roosting butterfly was a female and the other a male and the wing flicking was part of the male's courtship of the female. The wing flicking went on for a couple of minutes before the male gave up, realising its attentions were unwelcome and he moved on.

Male Wood White with wings spread molesting a female

A pair of Broad bodied Chaser dragonflies had also become active, sunning themselves on dead and broken bracken stalks. Dragonflies do not enthuse me as much as they do Peter but nonetheless they are attractively coloured insects although rather fearsome looking when examined closely.The stuff of nightmares but I have plenty of those at the moment thank you!

Broad bodied Chaser male

Broad bodied Chaser female
Slowly more Wood Whites emerged, their slow, ground hugging flight identifying them. We found others perched as well, looking transiently beautiful on blades of grass, Greater Stichwort and Tufted Vetch flowers.

These were the first brood of Wood Whites to emerge this year, there will be a second brood in July and August.

Wood Whites were the only butterfly we saw apart from a male Orange Tip which briefly settled to nectar on a vetch flower.

Orange Tip male
At around lunchtime we called it a day and it was just as well we did as an unwelcome and unpleasant heavy rain shower descended on the wood.