Tuesday, 20 June 2017

North by Northwest 15th June 2017

Two years ago in June I made my one and only visit to Handa Island which lies off the coast of Sutherland in northwest Scotland. This June a family holiday at Achiltibuie, an hour's drive south of Handa gave me the opportunity to take the family there and, of course, for me to make a welcome return visit to sample once again the delights of thousands of breeding seabirds but most of all the breeding Arctic and Great Skuas.

As before the weather was kind and apart from a brief shower on the fifteen minute crossing from the tiny mainland hamlet of Tarbet to Handa the sun shone constantly, the sky remained forever blue and the awe inspiring background of distant mountains created their usual magnificent spectacle and imparted their own special magic to the day.

The Cliffs at Handa Island
A brief talk from the warden in the little Bothy that acts as the focus point for visitors and then we were free to go and sample the delights of the island. Because of the ground nesting birds you have to keep to a part boardwalk, part track, which runs in a six kilometre circle around the island but this is no hardship as the skuas are often to be found near to the boardwalk or track and the seabirds breeding on the cliffs are easily accessible as the track runs right to the cliff edge. Indeed the skuas readily mob you when you get too close to their territories and they are constantly flying overhead at all times.

The Nature Table in the Bothy
Most visitors not un-naturally head for the seabird cliffs and especially the Great Stack of Handa, a huge tower of Torridonian Sandstone over one thousand million years old, to view the spectacle of thousands upon thousands of Guillemots, Razorbills and Kittiwakes lined along the precipitous ledges of the Stack, with the ultimate prize being the Puffins which are present in much lesser numbers than the other auks. The spectacle of thousands of seabirds come to land to breed never ceases to take my breath away. The sheer numbers gathered on the cliffs before me created an amazing sight and it has to be said sound. The birds were ranged in a downward heirarchy on the cliff face with first Puffins at the top, so they can use the burrows in the turf for nesting, then next are the Razorbills, each pair having a preference for a little personal space and a reasonably wide ledge on which to lay their single egg, to be followed by the massed ranks of Guillemots crammed in long lines, shoulder to shoulder on narrow terraces of ledges and finally, at the lowest level come the rows of Kittiwakes, each with its own nest to call home.

Wonderful as this was my focus was on the skuas and Arctic Skuas in particular. I have seen literally thousands of them passing various coasts of Britain as they make their migrations north or south across the sea but here on Handa I had the welcome and almost novel opportunity to see them on land and not just as moving shapes across a wide ocean. Arctic Skuas come in both a light morph and dark morph plumage and both were visible here. About the size of a Common Gull but with longer, more slender wings and pointed central tail feathers they are made for fast acrobatic flight and are supreme in the air, capable of the most amazing flying skills as they chase mainly terns and Kittiwakes to force them to disgorge fish from their crops.They are pirates in the true tradition, rakish, almost dandyish with their dark caps and plumage and with an indefinable charismatic even romantic presence.

Once they have finished breeding they migrate southwards across the seas and oceans to spend their winter far out to sea off the coasts of western and southern Africa. To watch them flying effortlessly on those long wings is to admire supreme elegance and grace.

Walking up the boardwalk we came to a pair of pale morph Arctic Skuas with a territory close to where we were standing. The birds rose from the moor grass, with yelping calls not dissimilar to a gull and soon were diving at us in an effort to dissuade us from coming any closer.They would sweep around over the moorland in a wide arc and rising up in the air before us would come in at speed on a steep dive only to rise at the last possible moment above our heads thus averting a collision before repeating the manouevre again and again until satisfied we were no longer a threat, perceived or otherwise.

We carried on up the boardwalk as now Great Skuas flew in synchronised pairs above us, their barrel shaped bodies, bulky and belying their similar supreme flying skills. On landing they would momentarily hold their wings widespread and raised above their bodies displaying prominent white wing flashes whilst bending their heads low to the ground in some form of display.

Great Skuas
We arrived at the cliff edge and looked over and across at the Great Stack of Handa. Far below us studded on the sea like so many discarded bottles were hundreds of auks whilst a constant stream of others arrived or departed from the cliff face or passed by in fast, low flying squadrons heading for cliffs further round the island. The loud incessant cries of Kittiwakes mingled with the low growls of the Razorbills and Guillemots, while Fulmars flew up on the air currents, rising ever upwards on stiff outstretched wings as if examining the cliff face before descending in a dizzying glide back down to sea level.The bird activity is at its peak at this time of year and the sky was constantly filled with birds going about their everyday lives. 

The Great Stack of Handa
Two Puffins perched precariously on a sloping ledge, their plumage a pleasing mixture of colours amongst the pink Thrift and grey green lichen clinging to the rock, the two tone black and white plumage offset by bright orange legs and feet and a multicoloured bill of outlandish proportions. They stood silently and hardly moving, as if in a constant state of mute complaint and surprise about all the vulgar noise and activity around them, occasionally being joined by another of their kind as if come to discuss the situation. A Fulmar, huge in comparison to the Puffins unceremoniously barged its way onto the ledge on which they were standing, and sank onto its belly as the Puffins discreetly moved away, looking even more affronted at this untoward intrusion.

Great Skuas prospected the cliff face looking for unwary Kittiwakes or an unguarded auk's egg or chick but they were confronted by such numbers of birds that they appeared confused and would drop away downwards on their huge dark brown wings  to glide menacingly across the sea. A Great Black backed Gull sat with bill tucked into its black scapulars, apparently sleeping in the grass on the cliff top but its eyes were constantly roving, looking for the slightest sign of weakness in the Puffins ranged along the cliff edge near it. It would easily swallow one whole given the chance.

We sat here for an hour or so on the springy green turf just enjoying the ceaseless, ever changing spectacle of activity but I became restless. I wanted to get some photos of dark morph Arctic Skuas and had noticed that a pair had settled near to the boardwalk we had walked up earlier.

I walked a few hundred metres back and found the pair of skuas alternately standing or sitting in the grass, a picture of contentment, but the minute another skua came near they would be on the alert and opening their bills wide would yelp in protest or warning and seemed especially annoyed or troubled by the Great Skuas. The dark morph Arctic Skuas look even more piratical than the light morph individuals and although not possessing the variety of colour tones are to my mind exceedingly smart in their dark chocolate plumage usually with a slightly paler buff patch on their cheeks and sides of the neck.

The warden told us there were thirty pairs of Arctic Skuas breeding on the island this year but in the last few years their success rate has been very low and no one currently can work out why. The majority of Arctic Skuas on the island are of the dark morph variety which makes sense as the lighter morph birds are  to be increasingly found further north, beyond Scotland in Scandinavia and Arctic Russia, whilst the darker morph birds tend to be found in the more southerly parts of their range. such as Scotland

Three hours had passed in seemingly no time at all and soon it was time to go back to the beach to meet the boat that would take us back to the mainland and a late lunch in the tiny Shorehouse Restaurant overlooking the slipway, and famed for its seafood and probably with one of the best sea views anywhere in Britain.

Thursday, 8 June 2017

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 in 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 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 Buckinghamhire and Oxfordshire by BBOWT (Berks, Bucks and Oxon Wildlife Trust) and others, have enabled the Black Hairstreak to increase and thrive although there is now a new threat caused by the burgeoning deer population browsing the Blackthorn.

When the M40 was constructed 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. But for the greater good I am content to suffer this inconvenience and after all is said and done there are plenty of other areas 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 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 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.

So it was that today Peter and myself rendezvoused at a suitable wood with copious amounts of Blackthorn growing at its edges along 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, 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 gusty 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.