Monday 7 August 2023

Hairstreak Gold 3rd August 2023

There are five hairstreak butterfly species native to Britain and the largest and last to emerge is, in my opinion, the best of all - the Brown Hairstreak, which traditionally flies in late July and early August and is with us until the end of September. All five species are rare and elusive and due to  habitat loss consequently endangered and none more so than the subject of this post.

Last year I made a cursory visit to a local site in my home county of Oxfordshire to try and see them but failed miserably and never got around to going back to try again.

This year the time of their emergence has coincided with continuous dreadful weather of rain and wind so it was hit and miss if I\could find a window of opportunity where the sun shone long enough to make it worth my while travelling to my favoured location in search of them.

I took a chance on Thursday and although it looked touch and go, for a time the weather relented to bring some warm sunshine but with a forecast it would cloud over by noon.

The location I go to is sheltered, so wind is rarely a problem on the narrow grass track that runs between overhanging trees and bushes, a mix of hawthorn, blackthorn, ash, elder, willow and oak with a tangled and riotous understorey of brambles, thistles, nettles, umbellifers, bindweed and willowherb. 

Its cloistered warmth and shelter provide a welcome benign environment for butterflies of a number of species but the Brown Hairstreak is undoubtedly the crown jewel.

The Brown Hairstreak's overall range has contracted by over 60% in recent decades and as a result they are a top conservation priority They are a butterfly of predominantly southern England with their northernmost colony located in north Lincolnshire and notable strongholds in West Sussex, Surrey, Buckinghamshire, Oxfordshire and North and South Devon.They are also found in Cardigan and Carmarthenshire in Wales and on The Burren in Ireland.

The main causes of their decline are the removal of suitable hedges from the countryside and farmland and the now normal practice of annual indiscriminate roadside cutting of hedges by tractor mounted flails as opposed to the traditional periodic manual, and consequently less brutal pruning of hedgerows.Brown Hairstreaks lay their eggs on the new shoots of blackthorn on which the larvae hatch and feed but many are now destroyed by the flails..

Fortunately the site I visit is protected and the hedgerows are sensitively managed to ensure the colony will survive and prosper..Unfortunately there is a cloud on this optimistic horizon in that the female Brown Hairstreaks can cover several square miles laying their eggs in suitable habitat and some of that habitat will not be protected and subject to flailing or even removal.

Brown Hairstreaks are late risers so I knew there was little point in arriving before around 10am as the sun does not penetrate between the hedgerows until then. Once the magic hour is reached it is a matter of patience until a hairstreak descends to nectar on the many thistle flower heads growing in the tangles of rampant vegetation or settles on the bramble flowers  festooned over the lower branches of hawthorn and blackthorn. So it proved this morning as I waited for the sun to slowly edge down onto the brambles and thistles.

It was no real hardship whilst waiting as it is quiet and tranquil. a balm for the soul, being surrounded by a profusion of summer vegetation and myriad insects. A Willow Warbler sang briefly, no more than a whisper of notes, a last farewell to summer. A Raven's staccato calling came from afar.  Amongst the ubiquitous Gatekeepers, winking their bright eyed wings in the sunshine and an  inquisitive Comma checking every intrusion into its self selected domain, I was entertained by a fresh Red Admiral, flirting its poster paint coloured immaculate wings on a bramble flower. It has been such a good summer for them, and they seem to be everywhere this year in large numbers, dashing away from leaf and flower at my approach only to circle and double back in erratic glides to settle once more.. Every hedgerow in this part of Oxfordshire seems to harbour them at the moment, this boldest and most obvious of butterflies, even out and flying in dull cloudy weather which other butterflies shun.


Red Admiral

I came across my first hairstreak at around 1030am, nectaring high up on a spray of bramble. It was nice to renew acquaintance with what I fancifully regard as an old friend..It brought that sense of continuity and renewal one feels after a long absence from someone you cherish and with whom you naturally feel at ease and content. 

However I soon began to wish for a closer, more intimate encounter, having from past experience had them literally at eye level and just inches away. My wish was granted sooner than expected as a pristine male, possibly hatched this very morning, descended to imbibe nectar from a thistle flower..

If you read about this hairstreak's life history and behaviour you are told that they spend most of their time high in the surrounding trees feeding on honeydew (the excretions of aphids) from the surface of the leaves and rarely come down lower to feed on flowers. Here that is not the case, in my experience, and if you wait long enough you are pretty certain to encounter one, if not more, at eye level or even lower, feeding on a thistle or bramble flower.

The male hairstreak settled low down on its selected thistle head and commenced a detailed examination of the pale purple florets for nectar. Round and round, both upright and upside down it explored every aspect of the flower head, probing with studied deliberation each tiny purple floret for its minute drop of nectar and then after a complete circuit of the flower, repeated the process as if concerned it had missed something. I watched for an hour and it was still on the same flower head when I left.

Others descended soon after I had discovered the first until there were four individuals in front of me each on their particular flower head and, like the first, never moving from their flower of choice. This was truly exceptional and something I have never encountered before in many years of watching Brown Hairstreaks here. Usually it is one or two, if at all, after a long wait  but today was different. 

It has been suggested that after prolonged rain, such as occured in the days prior to my visit the honeydew gets washed off the leaves and this persuades the hairstreaks to transfer their attentions to substitute sources of nectar such as thistles and bramble flowers.This could well be true in this case or possibly it was just a chance happening.In all I saw six hairstreaks, the other two being nearby along the path.

It was noticeable that when the sun was obscured by clouds a couple of individuals opened their wings to absorb any residual warmth and by so doing revealed a lack of orange markings on their chocolate brown upperwings, signifying they were males.It would have been nice to see a female as they have a large and attractive splash of orange on the upperside of each of their forewings but one cannot have it all and I was content to remain philosophical and enjoy the moment.The sight of any hairsttreak is one to be savoured no matter what.


Male Brown Hairstreak

There is one particular hotspot along the path where it narrows, sheltered and with an abundance of bramble as well as numerous thistle flowers and if one has to wait then this is the prime and most rewarding place to do it.

Brown Hairstreak heaven!

Brown Hairstreak is such an uninspiring and unimaginative name and does not do justice to this charismatic, beautiful butterfly. True it is brown when it opens its wings but as they mainly keep their wings firmly closed they appear pale orange with bands of richer orange bordered by delicate wavy threads of white. It is such a shame that a former name for them, Golden Hairstreak has fallen into disuse as this seems  much more suitable to describe this gem of an insect. 

So a pleasant few hours were whiled away as I stood in this sequestered, peaceful place with a couple of other enthusiasts for company, all of us enjoying the hairstreaks. Unnoticed the clouds began to gather and the sun slipped  away, my prompt to leave, well satisfied with my hairstreak fix for yet another year. 

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