A celebration of the Black Hairstreak: 7 – 10th June

This is an account of my quest to capture uncluttered images of a special butterfly. In Oxford we are not only blessed with the potential for finding more than 40 species within an hour’s drive of the city, but also with having one of Britain’s scarcest and most sought butterfly gems on our doorstep. I am referring to Black Hairstreak that occurs only in old woodland sites stretching from the outskirts of Oxford, north-eastward through Bucks’ Bernwood Forest complex into Northants and Cambridgeshire.

black hairstreak.1706

Mission accomplished – premium Black Hairstreak

This is an elusive butterfly with a short flight period, usually in the first half of June but possibly in late May after an especially warm spring. They are not easy to locate since most colonies, typically of a few dozen individuals occupy restricted areas of the woods where they occur, seldom moving far. On some days BH do not fly at all, preferring to rest out of sight in tree tops where they feed on aphid honeydew. But depending upon the availability of that sweet, sticky secretion they will also come lower to nectar on wild flowers such as Bramble, Dog Rose and Privet that grow amongst the Blackthorn food plant. Then these butterflies can compensate for their more usual inaccessibility by being very approachable.

In their regular Bernwood Forest strongholds, Black Hairstreak have been monitored for many years by expert naturalists active within Butterfly Conservation’s Upper Thames Branch. But an almost mythical status arising out of great scarcity also attracts collectors who can remove eggs and larvae, as well as inappropriate attention from casual observers. By the latter I mean the peculiar field underclass that is interested only in photographing Black and Brown Hairstreak, Purple Emperor and Large Blue. The conversation of such “butterfly tourists”, as I term them exhibits a lack of knowledge that matches their capacity for trashing habitat. And the result is pressure upon the most precious resource that the aforementioned butterflies represent.

black hairstreak_01.1701 finemere wood

One of Wednesday’s Black Hairstreak

Having myself become increasingly sensitive to that situation I dropped Black Hairstreak from my summer agenda in 2016. But this year I really rather fancied experiencing them again. Sightings began from 1st June just before last month’s mainly fair weather changed for the worse. Knowing Ewan’s yearly interest in these insects I tipped him off and he replied in the affirmative. My choice of location was BBOWT’s Finemere Wood reserve in Bucks. This is a well-known and monitored BH site over many years, so writing about it here can do no harm.

We met there at 10am on 7th June. Tuesday had been a cold and changeable day and this overcast morning had a definite hangover. No matter. We set off for what is known as one of the woodland reserve’s BH hotspots, and in still subdued conditions came across a first Black Hairstreak nectaring on Bramble flowers. BC UTB’s species champion, Stuart Hodges arrived shortly afterwards to fill us in on all things local BH. I have participated in his guided walks through this wood previously and nobody knows more about the butterfly than he.

We remained at this spot for some time, estimating that perhaps three BH were present. Usually in bursts of sunshine these butterflies would appear quickly around the Brambles before returning to the Hazel trees or tall stands of Blackthorn above. They were always restless, not settling for long and often leaning with closed wings sideways to the sun as BH do.

When I reviewed the above images at home my initial reaction was they were poor. So I turned to the editing suite to try to make them creative. But Hairstreaks are usually seen like this, constantly moving subjects flying jerkily against contrasting bright light and dark patchy backgrounds. They just don’t normally do uncluttered. On scanning back through previous seasons’ results those were all pretty much the same.

Eventually we moved on to check out another area of the wood that Stuart had cited as a hotspot. On the main ride we met a visitor from Dorset who had not seen Black Hairstreak before, and so took her back to the spot where we had been. It is always a pleasure to assist genuine and knowledgeable enthusiasts, as opposed to butterfly tourists in this way. Our guest was pleased to add a missing species to her British list and so be rewarded for a three hour drive. By this time conditions were mainly sunny and perhaps up to five BH were active.

In the early afternoon we visited another site where Black Hairstreak are being reported, finding a similar number again of always hyperactive butterflies. Here there was a lot of wild Privet growing amongst the Blackthorn stands, though the former was mostly still in bud. BH can be very tolerant of human presence when feeding on Privet, especially in cooler conditions and so I resolved to come back here to try for less cluttered pictures once that shrub is in more extensive bloom.

In the event things happened two days later. On Friday (9th) I spent three more hours at the second location. In changeable sunny and cloudy conditions I found about 10 Black Hairstreak in different parts of this wood but didn’t manage any pictures because none of them were settling. But I did make a thorough reconnoitre of the entire site to search out naturally occurring props on which butterflies might pose on a better weather day. There is something missing in each of the above two pictures. I was prepared for filling in the blanks to take some time but my goal was actually realised much more quickly.

Saturday morning (10th) was gloriously sunny with only very light cloud in the skies, and so I headed back here again. During the visits described in this post Black Hairstreak have mainly been encountered in small groups of three or four individuals. Today I was pleased to locate one such cluster very close to flowering Privet in a sunny place. So I staked out this spot waiting for butterflies to settle on the pungent smelling flowers and did not have very long to wait.

From time to time what was possibly the same BH returned to the Privet, but never settling for long and inevitably favouring darker recesses when it did. But occasionally over the next two hours it would settle on protruding flowers against lighter backgrounds. Then my camera would go to work mostly with disappointing results. The images (above) were all captured using my Nikkor 300mm telephoto lens that I have always found to be suited to insect photography.

Ultimately three butterflies became active at once and the longer I remained the more they seemed to become accepting of my presence, as insects do. Photography aside it was a superb experience to be so close to these rare and beautiful little jewels, and best of all was that I had them completely to myself. Now I decided to have a try with my macro lens. The BH allowed me to take hold of the twigs on which they were nectaring and manoeuvre them into a favourable light, whilst using the camera on auto focus with my other hand.

Almost all my macro work was over exposed and out of focus with one exception (above, left). Some people may object to this but I must stress that BH when nectaring are practically impervious to disturbance, as is well known. Also since my selected Privet was overhanging a public bridleway there was no need to wade into or flatten habitat, which in any case is something I take care to avoid doing. The other close-ups, taken into the sun were achieved with heavy editing (* lyric © I Astbury / B Duffy).

Black Hairstreak appear to be having a good year in 2017 as is usual following a warm May. The images in this post took around 12 hours in the field to secure over three days. I am very pleased with my insect observations so far in the early summer. After success in recording female Hairy Hawker (see here) and emerging Clubtail (see here) dragonflies, the Black Hairstreak butterfly has provided another long-sought result. Just over a week from the first emergences these most transient of butterflies are already showing signs of wear and tear. They will no longer be with us by the end of June.


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