Brown Hairstreaks at Otmoor 1st August 2018

A day of full sunshine, promised by the weather forecast, was a little slow in materialising but finally at about eleven in the morning it came to pass and I made my way to Oxfordshire's RSPB Otmoor Reserve in search of Brown Hairstreaks.

They are the latest of Britain's five hairstreak species to emerge, usually appearing in late July and continuing to fly throughout August and part of September. For me they are the favourite of all the hairstreaks, being the most colourful and largest, although there are plenty who would argue in favour of any of the other four species. Each have a hard to define star quality and all are eagerly sought after and bring a great sense of achievement when they are found. An audience with a hairstreak of any sort but particularly a Brown Hairstreak is undoubtedly a highlight in any butterfly enthusiast's year.

Brown Hairstreaks are not easy to find and can be frustratingly elusive and it often takes a considerable period of time standing in their favourite habitat before one is seen. There is, however, a good population of this butterfly in Oxfordshire centred around Bernwood Forest and it has expanded so much that individuals have even been seen in the cemetery by The John Radcliffe Hospital, close to the City of Oxford. Otmoor has, in recent years, become a popular site to seek out this butterfly and generally, with a little patience, they can be found but even here I sometimes  draw a blank and do not see one at all or the weather confounds me when the sun retreats as does the butterfly. They like sun and grey cloudy days, even when warm, are definitely not to their liking.

Often they will stubbornly remain perched high in a tree, usually an Ash and whatever the weather will not come down but at Otmoor there is one particular ride that has all the requisite habitat requirements and as a result they can often be found nectaring  low down on their favourite purple thistle heads and bramble flowers and this is what I was hoping for today.

There is little point in getting to Otmoor early as Brown Hairstreaks are relatively late risers and I usually get to Otmoor sometime between ten and eleven of a morning but today I was late and only arrived at noon, parking the car  and walking the short distance to the favoured ride whose grassy track is  bordered on each side by a profusion of blackthorn bushes, the Brown Hairstreak's larval foodplant, plus an agreeable mixture of ash and oak trees together with smaller hawthorns and sallows and a riot of summer tangled vegetation growing under and in front of the bushes and trees.

Having walked the few metres from the car and turned into the ride that was warm and secluded in the bright sunshine, I was bowered by the rampant vegetation, passing banks of willowherb and brambles, with bindweed flowing through and around them, betraying the course of their rambling green tendrils by thrusting up a blousy white trumpet of a flower at irregular intervals. 

I stopped after a few metres to examine a huge, sprawling and dense bramble clump, easily double my height, that tumbled down from the lower branches of some hawthorns to the very edge of the ride. Its rounded profile was a confusion of sun and shadow and littered with clusters of small pink blushed white flowers and already forming blackberries, that were attracting a myriad of insects such as hoverflies, small dragonflies, wasps, fragile silk white moths and sundry spiders, all seeking sustenance or security amongst the flowers and berries. Butterflies also came to take advantage of the bramble flower's nectar and two bright ginger Comma's wandered the flower heads, slowly flexing their wings in contentment. 

Comma

Lowly Meadow Browns, irrepressible Gatekeepers and Speckled Woods also joined the party.The joy of watching a bush such as this is that, often, an unsuspected butterfly will only betray its hidden presence when it flutters to move position, seek another flower to feed from or is disturbed by a bumbling wasp or bluebottle and this is precisely what happened as I stood contentedly in the sunshine.

Speckled Wood

A small brown butterfly fluttered up from an arching bramble spray and performed a fast jig around the leaves before dropping back onto a cluster of porcelain white bramble flowers, quite some way up on the bush. So far up was it, that it required my binoculars to ascertain what I thought and hoped it was. At first its tiny form was obscured by a cluster of buds and flowers but as it gently walked around it revealed it was a Brown Hairstreak. It was not in prime condition, with a nick out of one tissue thin wing, probably caused by an inadvertant snagging on the bramble thorns but no matter, here was my first of the season and found literally within minutes of my arrival.

For me the delight of seeing the Brown Hairstreaks at Otmoor is always tempered by an onset of slight melancholy in knowing that they are the last butterfly species to appear and signify that soon enough these lazy, bountiful days of late summer, with which I associate them, will be but a memory but for now all such thoughts of autumn were banished as I enjoyed the spectacle of the hairstreak going about its business.

I watched it for some time, even seeing it open its wings to reveal they had all brown upper surfaces which indicated it was a male, before it flew up and around the bramble and was lost to my sight. I moved on down the ride a short way, finding an even smaller butterfly, a tiny Brown Argus, that briefly sunned itself on a leaf before flying up and away. 

Brown Argus

A little further on I took a casual glance to my left which set my pulse racing as there, at just below shoulder height, was another male Brown Hairstreak. It was in absolutely pristine condition and perched full square on a small, purple thistle head, one of a few on an unremarkable and unlikely looking spray of Creeping Thistle thrusting up from the grass, nettles and bindweed.

This was what every butterfly enthusiast dreams of, a situation where you can photograph and admire this gem of a butterfly from as close as you could wish and from virtually any angle you may care to choose.

Its beautiful underwing pattern alternately shone in the sun or was lost in shade, dependant on the angle of the butterfly as it slowly meandered in and out of the sunlight, delicately feeling its way across the thistle head, examining in detail each miniscule purple floret. The underwings are washed  pale brownish orange and fringed white at their extremities with two irregular gashes of darker, brighter orange crossing each wing, both upper and lower. These gashes are bordered with the thinnest of black and white lines, the latter giving the butterfly its generic name of hairstreak but the glory of this subtle and pleasing arrangement of colour is not left there, for almost at the base of the lower wing are two short spurs which are yet another shade of bright orange as is that part of the wing between the spurs and the very hindmost lowest edge. All this can only be seen when the butterfly is viewed as close as this one was today.

To see this elusive insect so well and to be able to admire it for a prolonged period was almost overwhelming. The joy of the subtle colouring and to be able to marvel at such a beautiful creation of nature felt almost a rite of passage and a genuine privilege. I stood and took many photos as did Chris a fellow enthusiast I encounter occasionally on forays such as this. The hairstreak was intent on feeding and nothing would disturb or distract from this, as it minutely examined and probed every part of each small flower head. Like some ballerina or supreme trapeze artist it tripped around the flower, delicately clinging to the purple spikes with its thread thin legs, probing continuously with its proboscis, at first upright but then proceeding around the flower until it was upside down before returning to the top of the flower once more. 

We must have watched it for thirty minutes before it flew up a short way into a hawthorn behind the thistles and perched on the leaves, facing out over the ride. 

We accepted that our time was up, considered ourselves truly blessed and turned to walk a few metres further down the ride. A few minutes later, after looking at some other suitable habitat in the hope of finding another hairstreak I turned to check the thistle heads and there was the hairstreak back again! We returned at the double and resumed our one sided admiration and homage to this tiny insect. It was oblivious to any close attention we gave it and we photographed it from every angle possible. After another long spell of feeding it flew back up into the hawthorn but shortly after flew back down and resumed feeding on the thistle head. This was something I had never encountered before as normally once they fly off it is all over and they do not return  but today it was definitely not the case. Chris had to leave but I carried on my vigil, now alone in the ride. I estimated that the hairstreak had been feeding on the thistle for at least an hour and showed no signs of wanting to leave but fed constantly. Surely it had found every bit of nectar on the thistle head but obviously it had not.

Disturbed by a fly it flew back up to the hawthorn yet again and then after a few minutes was back for more. The hairstreak was immaculate, not a tear in its wings or any mark on the undersurface of the wings, so I speculated it was newly emerged and probably was fuelling itself as much as it could but I have also heard that in this year of exceptional heat and drought it might be that the aphid honeydew which they imbibe from leaves high in the trees is lacking, due to the heat either affecting the aphids or the surface of the leaves being just too hot and therefore the butterfly has to find another source of food. This seems quite a plausible hypothesis and would explain this hairstreak's extraordinary behaviour. Anecdotal evidence about Purple Hairstreaks coming unusually low to nectar this year is also well known and Matthew Oates, the Purple Emperor fanatic is also of the opinion that this year Purple Emperors have foresaken the tops of the Oak trees where they like to perch as the heat is too much and have come lower to perch in the moister, more shaded, lower strata of bushes below the trees. 

Another butterfly enthusiast came along the ride and stopped some twenty metres from me and crouched down looking intently into the vegetation. I walked along to join him and as I suspected he had found yet another Brown Hairstreak nectaring on another inconsequential thistle head.This one too, refused to budge. We got talking and I showed him the Brown Hairstreak I was watching and then we moved on to the bramble clump where I had seen my first Brown Hairstreak and found another three Brown Hairstreaks fussing around the bramble flowers. In all I had encountered at least eight Brown Hairstreaks in the space of a few hours, where normally two or three at the most could be expected, and that would be on a good day.  It really was quite a remarkable afternoon and I finally left the ride at half past three with both hairstreaks still feeding on their respective thistle heads. I estimated that the hairstreak I  had been watching virtually constantly on a thistle head had been there for at least two and a half hours and the other further up the ride had been present for at least an hour and neither showed any signs of wanting to leave as I departed.

A truly exceptional afternoon and one of those unexpected and inconsequential experiences that can and do bring such spontaneous joy. Simple pleasures!

Postscript

Such was my enthusiasm I returned to the ride at Otmoor this afternoon, the 2nd of August, and would you believe it the same Brown Hairstreak was on the same thistle head as yesterday and had apparently been there for at least a couple of hours and remained there for the hour I was present. I did not take any more photos as how could I possibly improve on yesterday but I did stand almost nose to antennae with the hairstreak and examined it in minute detail. This tiny insect, hardly bigger than my thumbnail was within a couple of inches of my face and I looked into its fathomless, unknowing black eyes  and its cute, pale, alien face. 

It was a unique experience, quite moving in its intimacy and I walked away feeling somehow uplifted for having this briefest of communion with perfection.

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