Sunday 16 June 2019

Black Hairstreaks at Last! 14th June 2019

After a week of almost incessant rain the weather finally relented at noon today and so sunshine and blue sky took centre stage. I lost no time in heading for a favourite location where I hoped that, just like me, Black Hairstreaks would be making the most of the sunny conditions. 

At last I was in search of butterflies!

The stands of thick Blackthorn interspersed with flowering Wild Privet that I had in mind provide the optimum habitat for Black Hairstreaks, this most sought after of butterflies and the first and rarest of our native hairstreak species to commence flying. Superficially they are not very colourful and certainly are misnamed by being called 'black.' They are, in fact, dark brown with narrow bands of orange on their upper wing surfaces. The underwing is paler mouse brown with a band of orange at the upper and lower wing's outer edges, the orange bordered on each side, in the case of the lower wing, with narrow lines of white and black dots. A subtle beauty which may be more appreciated by the committed enthusiast rather than the casual observer.

I parked my car by the discrete entrance to the small wood and on getting out was immediately rewarded with the sight of a Black Hairstreak flying across the quiet country lane to the hedge on the opposite side.

I turned to walk down the narrow footpath leading into the wood and looking up I saw yet more hairstreaks flying around a  hawthorn  that was entwined and embellished with the stems and pink flowers of a briar rose. The tiny dark forms of the hairstreaks flitted around at height but occasionally one would explore lower but they rarely settled. Examination of the wild privet flowers growing in the hedgeline by the lane failed to locate even one hairstreak nectaring which is unusual, so I moved deeper into the wood's dense stands of blackthorn and small oak trees. Here I saw many more hairstreaks as I stood enjoying the warmth of the sun which was illuminating the bushes all around me. 

At first I was tempted to walk the path looking for more hairstreaks but then decided to just stand in what I suspected was a favoured area and let them come to me. Black Hairstreaks prefer, above all else, areas of blackthorn that are both sheltered yet open to the sun and its warmth. It worked like a charm as a procession of this tiny butterfly flitted around the blackthorns and settled on the narrow dark green leaves seemingly intent on imbibing honeydew from both the blackthorn and the broader, larger oak leaves. Others would settle not to nectar but to angle and tilt the surfaces of their closed wings to the sun. They rarely settled for long but just enough for me to have an opportunity to take a photo or two of them as they sucked up the honeydew from the leaves.

It is always difficult to assess how many hairstreaks are around. Here they frequent quite a small area of the wood only and as they constantly jink and bounce around the blackthorns, then fly up and over the bushes only to return, I wonder are they different individuals or the same ones seen repeatedly? I think the former and I considered there were up to thirty or forty coming and going  in what was after all  this comparatively limited area of blackthorn within the wood. 

This butterfly has a very restricted range. being confined to just four counties Northamptonshire, Cambridgeshire, Oxfordshire and Buckinghamshire and seems incapable of expanding despite suitable habitat being available in other areas of the aforementioned counties. Like last year, on the evidence before me today of so many butterflies flying around, it is going to be a good year for Black Hairstreaks but what this continued awful spell of June weather may pressage for next year we can only wait and see.

Although it is said that this butterfly is hard to find and often a colony only consists of a small number of individual butterflies, here in this particular wood, for this year and last, it is thriving, very obvious if you know what to look for and there are considerable numbers present.

This wood is, as I said, an area much favoured by this fussy butterfly and there are other areas nearby where it is also to be found and I am indeed fortunate to have them living so comparatively close to my home.

I walked back to the lane and wandered along it looking at the white and waxy wild privet flowers in the hedge and unlike last year, when many hairstreaks were nectaring on the flowers, this year they were virtually absent, apart from just two or three scattered individuals. 

Last year was warm and hot at this time of year and maybe the honeydew they prefer to feed on had dried out on the leaves, so they resorted to the privet flowers for sustenance. This year with the continuous wet conditions the honeydew is more available and this may explain the Black Hairstreak's absence from the privet flowers.

Whatever the explanation I had a relaxing and enjoyable few hours communing with this charismatic and rare little butterfly and hopefully the weather may improve enough to allow me one more day to go and see them before it is all over for this year.

No comments:

Post a Comment