Black Hairstreaks 7th June 2017

There are five species of hairstreak butterfly that inhabit Britain and the rarest of them is the Black Hairstreak, with many enthusiasts travelling long distances to see them during their very short flying season.

I am fortunate that I live in Oxfordshire which is one of the strongholds of this butterfly in its very restricted range. They are only found in a string of ancient woodlands, relics of a once continuous forest that extended from Northamptonshire in the north, southwards through Cambridgeshire, Huntingdon, Buckinghamshire and Oxfordshire. The reason they are so restricted is that they do not disperse widely as they are very reluctant to fly any distance and it was only in the former extesnive forest that the continuous history of traditional woodland management  proved beneficial to Black Hairstreaks. This traditional form of management ceased around the end of the 19th century and as a consequence many colonies of this small butterfly died out but since then conservation efforts in the fragmented remains of the forest, especially in Buckinghamshire and Oxfordshire by BBOWT (Berks, Bucks and Oxon Wildlife Trust), have enabled the Black Hairstreak to increase and thrive although there is now a new threat caused by the burgeoning deer population browsing their foodplant, Blackthorn.

When the M40 was constructed through Oxfordshire some twenty years ago, an area of several hectares called the M40 Compensation Area abutting Bernwood Forest was created specifically for Black Hairstreaks. It was highly successful and a very large colony of Black Hairstreaks has now become established there. On recent annual visits I can recall seeing double figures of this enigmatic butterfly nectaring on a Wild Privet bush within metres of the forever busy and noisy Motorway. However, as of this year I can now no longer go there as the whole area has been 'deer fenced' to protect it from deer, as their browsing was degrading the habitat. For the greater good I am content to suffer this inconvenience and after all is said and done there are plenty of other areas nearby to seek out Black Hairstreaks, as evidenced below.

Black Hairstreak colonies are usually small, consisting of no more than a few dozen individuals but after a warm Spring such as this one numbers can be considerably more, and conversely, less after a wet, cold Spring. The colonies are often  restricted to a small, favoured part of a wood such as a sunny glade or ride with plentiful amounts of unshaded Blackthorn growing along sheltered edges of woodland and with Bramble, Dog Rose and Wild Privet flowers for the butterfly to nectar on. Fortunately this habitat is not in short supply in Oxfordshire and Buckinghamshire 

The first individuals are on the wing from about the first week in June onwards, give or take a few days, but the adults are only on the wing for a very short time and usually have gone by the first week in July. They are elusive, spending much time in the canopy of higher trees feeding on aphid honeydew, sometimes hardly ever descending lower but if you are lucky and patient they can be found, having flown down to nectar on their chosen flowers and then are very tame and approachable, so much so you can, with a little patience get them to walk onto your finger. Believe me I have done it!

Black Hairstreaks are not black but are brown and in fact they are quite plain.The upperwings are dark brown with small orange bands at the edge of the wings, more prominent on females.The underwings are a paler mouse brown with a broad orange band on the lower hindwing and a row of black and white spots along the inner edge of the orange band.The distinctive white 'hairstreak' runs across both underwings.

Black Hairstreak

So it was that today Peter and myself rendezvoused at a suitable wood with copious amounts of Blackthorn growing at its edges along the aforementioned sunny sheltered rides, the Blackthorn interspersed with the hairstreak's three nectaring plants. 

I was glad to be looking for Black Hairstreaks today as it is best to get out early in the hairstreak's short flying season in order to see them when they are newly emerged and are less likely to be showing signs of wear and tear. One also has to remember our capricious weather and that opportunities to see them flying can, and frequently are, limited by adverse weather.

The forecast for today was sunny spells but when we met at ten am it looked anything but, with much grey cloud, a gusting wind and little sign of sunshine. Undeterred we walked towards the wood and took a small ride to our right, bordered on each side with large mature Blackthorns, that wound its way into the green recesses of the wood, 

Black Hairstreak habitat

We came to a suitable patch of Bramble and stood by its delicately tinged pink flowers and looked but there was not a sign of any butterflies let alone a Black Hairstreak. Slowly though, the cloud was breaking up and occasional brief interludes of sunshine illuminated the Blackthorn. We split up with myself standing by the Bramble patch waiting, more in hope than expectation, for a hairstreak to fly down to nectar on the Bramble flowers whilst Peter walked on further to see if there were any other suitable patches of Bramble where a hairstreak might be found.

Ten, maybe fifteen minutes passed and I heard a vague cry from a now distant Peter. This could only mean he had found our quarry and I hastened up the track, the long lush grass brushing my trousers and taking care not to  crush the numerous Common Spotted Orchids, their pale purple flower spikes like so many church spires in the grass.

Common Spotted Orchid

I turned a corner and there was Peter photographing a Black Hairstreak nectaring on a generous patch of Bramble flowers. the familiar little triangle of closed brown wings was clearly visible as it delicately wandered over the petals with its proboscis between its legs, lapping up the nectar from the flowers. It was here for about five minutes but the occasional gust of wind made it flustered and it would flutter about before settling again but always moving higher before finally jinking its way up and over a Hazel tree standing behind the Bramble.

Black Hairstreak

Neither of us were truly satisfied with this brief view and decided to wait and see if it or another came back. It was not unpleasant now, as the sun was more continuous and it was quiet and secluded with just the two of us standing in the ride.The sunshine had brought out other butterflies too and we were visited by Red Admirals, Speckled Woods and I saw my first Large Skippers for this year.

Red Admiral

Speckled Wood

Large Skipper

After a while, and a little bored I walked twenty or so metres back down the ride to check another Bramble patch but was unsuccessful in finding any hairstreaks. I did however notice an area of slightly trampled grass below the Blackthorn and looked closer. Initially I could see no reason for anyone being interested in this part of the Blackthorn hedge but by chance the night before I had seen an image of a Black Hairstreak Chrysalis, which is a marvel of camouflage, looking just like a tiny bird dropping and is usually placed on a Blackthorn leaf or stem.

I looked closer, at first seeing nothing untoward. But then, yes, there right before me, on a shiny Blackthorn leaf was a tiny dark lump with a white mark at its centre. It was a Black Hairstreak Chrysalis. I was overjoyed  as this was a great find and something I had never seen before nor ever expected to find.  I called Peter and together we marvelled at this tiny vestige of the Black Hairstreak's life cycle. Reading up  about this I learnt that despite the superb camouflage many are predated especially by Willow Warblers!

We went back to the original Bramble clump to find the Black Hairstreak had returned or maybe it was another. We watched as it did pretty much what the previous one had done, nectaring on the Bramble flowers but again the gusting wind made it fidgety and like before it flew up and over the trees behind. Several more hairstreak visitations came and went before we decided we had enough.We estimated we had seen between three to five Black Hairstreaks but for me the great prize was finding the Chrysalis.

We visited another suitable area of habitat a short drive away where the main nectaring plant was Wild Privet and found another four Black Hairstreaks there, so maybe this is going to be a good year for them. I do hope so.

Close Encounters of the Cuckoo Kind 4th June 2017

A couple of weeks ago I was in a dilemna about going to see a Night Heron in Shropshire or a Common Cuckoo, which was so confiding it bordered on the ridiculous, frequenting Thursley Common in Surrey. In the end I opted for the heron and put the cuckoo to the back of my mind.

Yesterday, Saturday, I spent a happy couple of hours at Otmoor RSPB, my local reserve, watching amongst other birds Common Cuckoos, which this year are the most abundant I have ever known them to be on the reserve. Rather than just encountering single birds as is usual, this year you are more likely to see them flying in anything up to groups of three or four and amongst them there is also one of the rare hepatic females in which the grey feathering is replaced by brown.

I met Mark and Pete on the bridleway and we were discussing the plethora of cuckoos on the reserve when Mark in passing asked if I had been to see the Cuckoo, namely the one on Thursley Common. I told him that events had just got in the way and anyway it would be long gone now as over two weeks had passed. 'Well it was there last Saturday and as far as I  know is still performing' replied Mark.

There and then I resolved to make the trip to Thursley the next day, Sunday, in an attempt to see this famed Cuckoo. Mark had earlier given me verbal instructions as to where to find it on Thursley Common so all I needed to do was muster the willpower to rise early on Sunday morning and make the two hour drive south to rural Surrey.

Sunday dawned bright and sunny and I was set fair for Thursley Common. For once it was a pleasure to drive the Motorways, as an early Sunday departure meant comparatively little traffic and I was soon driving down a minor road from the village of Elstead  which led me to The Moat car park on the opposite side of the road to Thursley Common.

Following Mark's instructions I headed off into the wide heathery expanses of the Common following the trails he had told me to. 

At least that was the plan but somewhere I went wrong and could not find the large metal dragonfly which was the main landmark Mark told me to look out for. I retraced my steps almost back to the road and encountered three lycra clad lovelies and asked them if they could direct me to the metal dragonfly. They then had a bit of a conflab amongst themselves and voted two to one that I should follow the sandy track they indicated to my left and which I had somehow missed.

Following this track I came to the shining metalwork of the dragonfly without too much bother and then all I had to do according to Mark's instructions was follow the right hand track and I would come to a wood and passing through that would find a gate which led into a large field surrounded on all sides by trees. This is where the Cuckoo would be found, coming to feed on mealworms placed on a wooden perch especially erected by photographers.

Easy then? Not a bit of it. I got lost again and rang Mark who wisely but sadly for me had turned his phone to silent. I left a text message in the hope he would get it eventually but in the meantime I was at a loss as to where to go. Half an hour of aimless wandering on the vast acres of Thursley had got me no nearer the hallowed field although I did see and hear a Cuckoo calling in a Silver Birch.Was this the particular Cuckoo I had come to see? I had no idea.

Mark eventually called and I found that, although well off course, I was not that far away from the required location and with fresh instructions from a very patient Mark I was on my way towards the wood on the other side of which was the field. As I walked towards the trees two Cuckoos flew along the side of the wood and disappeared. 

The Cuckoo field surrounded by trees

I soon found the field, currently with six people standing some twenty metres in from its edge presumably waiting for the Cuckoo to appear on an obviously prepared perch consisting of a propped up branch and some logs that had been erected by photographers. 

The artificially constructed perch awaiting the Cuckoo

Awaiting the Cuckoo

I joined the small gathering,and was pleasantly surprised to find two were birding colleagues from Sussex, who gallingly told me I had just missed a visit by the Cuckoo, so we had  a chat and I settled down to wait for the Cuckoo to re-appear. It was now around 9.30am and my two friends having already seen the Cuckoo decided to leave which left just me and four others to while away the time anticipating the imminent arrival of the Cuckoo.

Whilst waiting we were entertained by a wondrously smart, male Common Redstart that had young in a hole in a nearby Silver Birch and was busily coming to collect the mealworms that were placed on the perch for the Cuckoo. You could hardly begrudge its taking advantage, especially as it was so photogenic. We only saw the female Redstart once but the male came back time and again and we began to worry that we would run out of mealworms for the Cuckoo. Depressingly, an hour had passed without sight or sound of the Cuckoo, as we were joined by a young boy and his father also keen to see the Cuckoo.

Common Redstart-male

Two Woodlarks wandered through the grass and a little later the lovely melancholy song of the male drifted across from the heathery expanses beyond the field as a couple of Mistle Thrushes searched for worms in the shorter grass. A distant Garden Warbler sang from the bushes behind us and a Green Woodpecker flew in looping bounds across the field but there was still no sign of the Cuckoo. Two hours had slowly passed before we heard the Cuckoo calling from the trees at the end of the field. Silence then reigned for another fifteen minutes before we saw it flying across the far end of the field but it seemed disinclined to come to the prepared perch, For the next twenty minutes it flew and perched amongst various trees around the field raising our hopes that it would finally come to the perch and at last it flew directly towards the perch, calling as it did and landed in a flurry of grey and barred white feathers at the top of the perch.

We were but three or four metres away from it but it showed not one iota of fear and stared at us with an expressionless yellow eye before setting about the mealworms. I had been told it would remain for some time on the perch, feeding on the mealworms, but after ten minutes it flew off. I wanted more. To be so close to the Cuckoo was great, but for only ten minutes after such a long wait, not so good from my point of view. Twenty minutes passed with the Cuckoo still hanging around in the nearby trees bordering the field although often out of sight.

Then suddenly and unexpectedly it called from right behind and above us.The beautiful, mellow two note call was incredibly loud. It had, as Cuckoos often do, silently and surreptitiously arrived in the top of a medium sized tree just a few feet behind us. Then it flew again to a more distant tree but after a brief spell perched on an exposed branch, flew once more towards us and landed on the perch.This time it remained for a good twenty minutes feeding on the mealworms, both on the perch and on the ground.When on the ground its short feathered legs were very apparent as the bird hopped clumsily in the grass, looking distinctly uncomfortable and it would remain motionless for up to a minute looking around, its barred underbody sunk in the grass. 

Its legs and feet were bright golden yellow and when perched on the logs I could clearly see the distinctive zygodactyl feet where the first and fourth toes point backwards and the second and third forwards.They share this characteristic with woodpeckers and parrots, and it is thought to be an adaptation for climbing and clinging. In the Cuckoo's case it is not quite clear why it exists but may facilitate the young Cuckoo in gripping the side of the nest as it ejects the host species young or eggs and later, when almost fledged, its bulk requires it to hang on to a nest that is on the point of collapse.It may also assist the adult female when she lays her egg in the host 's nest.

The zigodactyl feet are displayed to good effect in the above three images

Cuckoos have been written about from as far back as the time of Aristotle in 300BC and before the concept and existence of migration was known, the Cuckoos that came to us in summer were thought to change into Sparrowhawks in the winter. If birds possess charisma then the Cuckoo certainly qualifies. At such close  range I just stood and admired its pleasant combination of grey upperparts and barred underparts. Its underwings were also profusely barred and its long graduated tail had a series of white notches on the edges and tips to the feathers. The long pointed wings, long tail and slender elongated body render the Cuckoo larger in appearance than it actually is and its flight can be both accomplished and fast, often low to the ground, again similar to the flight of a Sparrowhawk.

Superficially it does look very much like a Sparrowhawk and this similarity is thought not to be coincidental. Originally it was considered this hawk like appearance was to intimidate potential host species but several experiments have shown that the Cuckoo's appearance evokes precisely the opposite reaction, with smaller species of birds violently attacking stuffed Cuckoos placed near their nest. Another possible theory is based on the fact that Common Cuckoos are mostly solitary, spend a lot of time sitting on relatively exposed perches and feeding in the open and the Cuckoo's hawk like appearance deters other raptors such as Sparrowhawks from attacking it.This would apply not only when it is in its summer quarters but also on migration and in its winter home in tropical Africa. 

I looked at the Cuckoo and wondered at this bird and the many lands it had crossed and the places where it had searched for food and slept in its life. According to one of the other people present today this is the third year this particular Cuckoo has been back, which is remarkable considering the dangers it and its fellow Cuckoos must encounter on their migrations back and fore across the Equator. Towards the end of this month it will be on its way south on another great journey. What does it see at night as it migrates over the great illuminated cities of Europe, thence travelling both night and day in a long journey of over three thousand miles including crossing the vast hostile emptiness of the Sahara which it must cross non stop or it will perish. Research on Cuckoos travelling from Hungary to Africa has found they cross the Sahara Desert at an average speed of sixty km per hour and at a height of between three to six kilometres! Having cleared the desert they then fly onwards across the tropics and the dense, trackless, humid and steamy jungles of central Africa to their southern Africa home, there to spend a peripatetic existence for a couple of months feasting on caterpillars in the rainy season before making another hazardous return journey to northern Europe. I can remember sitting in a friend's garden in northeastern Zimbabwe years ago and encountering no less than seven species of cuckoo including our Common Cuckoo, feeding on an epidemic of caterpillars in the shade trees but once the caterpillars were gone so were the cuckoos.

I looked at this bird and its life, another marvel of our natural world, somehow surviving the perils of a very uncertain future. I looked up to the sky and my thoughts travelled further to the horrific events of last night in London and Manchester two weeks ago and I felt so sad that such beauty and wonder can still exist in a world where there is nothing I can do about the senseless, pointless, cowardly barbarity and intolerance shown to my fellow men, women and children  I looked back to the Cuckoo and well ................