Thursday 29 August 2019

Black Terns 24th August 2019


With a welcome change in the weather to gentle southeast winds, soaring temperatures and full on sunshine it was like the Mediterranean at Farmoor Reservoir on Saturday as everyone donned summer clothing  and sat outside the yacht club to enjoy the al fresco delights of a Hackett's coffee and slice of cake.

We were not the only ones to take advantage of this 'Indian Summer' as the change of weather persuaded Black Terns to embark on a mass movement across southern Britain as they headed south to their winter home in tropical Africa. From Somerset in the west to Essex in the east Black Terns were being reported in large numbers today from many and various inland waterbodies.

Farmoor proved an attractive stop over for some of these migrating terns and an initial thirty soon doubled to an estimated sixty plus. I was at the RSPB's Otmoor reserve when the news came through and rapidly made my way to Farmoor but I was too late to see this large flock of Black Terns as many had departed, doubtless making the best of the weather conditions while they lasted to get as far south as possible.

Nevertheless there were still around twenty five Black Terns, a mixture of adults and juveniles lingering and patrolling up and down on Farmoor One, the less disturbed and smaller of the two reservoirs.

I rather like Black Terns, the second smallest tern to visit Britain. They do not have the  tail streamers of Common or Arctic Terns and their wings are slightly shorter and broader although still imparting an elegance to their flight. Both the Common and Arctic Terns and the smaller Little Tern feed mainly by plunge diving for fish whereas the Black Tern feeds by picking insects off the water's surface or from the air with swoops and glides, in a flight of some buoyancy and grace. 

Black Terns, which formerly bred in England up to the middle of the nineteenth century have not done so since, but breed on mainland Europe as close as France, Belgium and the Netherlands extending northwards to Germany, Denmark and southern Scandinavia and east into Russia. They are, however, still regular passage migrants to southern England in Spring and even more so in Autumn.

I took some photos of the Black Terns as they followed a circular course around the reservoir, always in a loose association, dipping and rising endlessly over water that sparkled in the bright sunlight. They were still at Farmoor in the evening but most had gone the next day. 

They still had a very long way to go.



My grateful thanks to Ian Lewington for pointing out this bird is a juvenile with a displaced primary.
An adult would have symmetrical moult i.e the same primary being moulted in both wings not just one


Adult Black Tern in  almost full winter plumage but still showing traces of black breeding plumage on
its underparts









Wednesday 28 August 2019

Chasing The Scotch Argus 25th August 2019


Three days of consistently hot and sunny weather and, for once, coinciding with a Bank Holiday was the trigger to make a long trip north to Cumbria in order to try and see Scotch Argus butterflies which are only found at two sites in England, Arnside Knott and Smardale Gill, both of which are in Cumbria. I had told Peter some time ago of my intention to go north if the weather proved favourable but it was only since Saturday that a suitable weather window of opportunity presented itself. 

It was getting a little late in the season as Scotch Argus rarely last into September and probably would not be at their best but as with all butterflying in Britain it is the weather that governs when you go seeking butterflies and the weather this August has not been the best.

I called Peter and we arranged to go to Cumbria on Bank Holiday Sunday, reasoning that the traffic would be light in the middle of the Bank Holiday and so it was to prove after Peter came to my house at 5.30am and we embarked on the four hour drive to Cumbria.

Our destination was Arnside Knott. Last year I had seen my first three Scotch Argus here after making an impromptu stop there on my way south from Scotland with Mrs U but the views were not the best so I was keen to do better. Peter had never seen this butterfly so it was imperative that we should succeed in our quest.

After a long, tiring drive in light traffic with a couple of stops to take a break from driving, we arrived at Arnside Knott just before nine on a lovely sunny morning with not a breath of wind. Arnside Knott has a reputation for being a prime butterfly location, its two main claims to fame being that a healthy population of very rare High Brown Fritillarys used to be found here but these are dying out and on a visit two years ago Peter and myself failed to locate even one. Arnside's other claim to fame is that it harbours the southernmost population of Scotch Argus in Britain. This time the curse of Arnside  struck again as we failed miserably to find any sign of a Scotch Argus although they are meant to be here in good numbers. (We were told later that it had been an exceptionally bad year for them at Arnside)

After an hour of slogging along the steep slopes of Arnside all we had seen were a very tatty Wall Brown, one Northern Brown Argus, the inevitable Painted Ladys and a few each of Gatekeeper and Meadow Brown. It had been a long and wearisome drive and here we were confronted with total failure. I was tired and tetchy and loudly cursed Arnside Knott, vowing never to return. Whatever is the cause of its demise as a premier butterfly location I have no idea, maybe the conservation of the habitat is not right. Who can tell - but something clearly needs to be done.

Thankfully we had the fall back option of Smardale Gill NNR, the other site for Scotch Argus in England, otherwise it would require a visit north of the border which was out of the question today. With rare foresight I had made a note of Smardale Gill and its postcode before we left Oxfordshire and we now put this into the Satnav and headed even further north towards the small town of Kirkby Steven in the Cumbrian Fells.

Fifty minutes later we turned off the main road to Kirkby Steven and took a single track road winding into the fells amid some exceptionally beautiful scenery. I had no idea what we would find at Smardale Gill or where to go when we got there but was pleasantly surprised to find a small car park for visitors and a Cumbria Wildlife Trust reception hut attended by two very friendly voluntary wardens who gave us a map and directions to where we could find the Scotch Argus. It was that straighforward.

Smardale Gill is both an NNR (National Nature Reserve) and SSSI (Site of Special Scientific Interest), managed by Cumbria Wildlife Trust and is based on  a former railway line that carried coke from County Durham across The Pennines to the steel works at Barrow in West Cumbria, and since closure the line has been converted into an all weather track that runs along the side of a steep valley passing through truly spectacular scenery.The kind of scenery that lifts the heart and makes one rejoice to be alive. On a day like today, of full sunshine, it looked at its absolute best. The track we were to follow ran for one and half miles to Smardale Gill Viaduct, itself now part of the reserve.


The track faithfully following the course of the railway line
with the flower rich butterfly verges on either side
At first we passed through gentle woodland, with little sign of any butterflies apart from an occasional Speckled Wood.We passed under a span of the truly awsome viaduct that carries the heroically engineered Settle and Carlisle railway north to the Scottish border and that, thankfully still operates to this day. We continued following the track and eventually it opened out to allow sunshine to fall unhindered on wide verges full of mauve scabious and deep pink knapweed flowers being attended by a host of butterflies.



I think it fair to say that neither of us had seen quite so many Peacocks, butterflies that is, in one place at one time.They were literally everywhere you looked, on either side of the track, each perched on a flower with wings closed forming black slightly sinister triangles or with maroon red wings spread wide, showing a glory of four multi coloured  eyes, one to each wing. In a space of a few metres you could easily count ten at a time, nectaring as fast as they could on the abundant scabious and knapweed. Spectacular as this sight was and tempting to tarry a while, it was not our main purpose for being here and we were impatient to find a Scotch Argus. Surely they must be here?


Peacock
To Peter went the honour of finding our first Scotch Argus as he exclaimed 'Here's one!' and there indeed was his first ever Scotch Argus, a little worn and frayed but irredeemably a Scotch Argus. 


The first Scotch Argus we found.Not in the best condition but a
very welcome sight indeed after our failure at Arnside Knott
High fives were exchanged and then we set about trying to find more. Relaxed now, after the anxiety of whether we would actually ever see a Scotch Argus after our failure at Arnside Knott, we ventured slowly along the track. Would we see more? You bet we did. They were now everywhere we looked, concentrated into a hundred metre or so length of the track, their curious hesitant and fluttering flight looking weak but actually nothing of the sort, as they fluttered up and down the embankments, settled to nectar on the flower heads or bask in the sun, low down amongst the grass stems. 









We were calling out to each other in our excitement as we found one after another but eventually calmed down to concentrate on getting a good photo of this, the handsomest of the satyrine brown butterflies.




Many were males that flew in their strange hesitant flight, rather like a Wood White's low level wavering progress and they appeared to be flying on a quest for a female to mate with. Some were very much past their best with worn, faded brown wings made ragged from rummaging in the grass but others were fresher and darker brown. The males would investigate anything brown and on a number of occasions would approach a Peacock before realising their error.



They are a quite beautiful butterfly when seen close. The dark chocolate brown on their upperwings is marked with orange bands on the forewings encompassing  black spots with white centres and there are similar bands on the hind wings but with less distinct spots. The underwings seem to vary, with males showing another band of orange with spots on the upperwing but a broad grey band running across the hindwing.The female is paler, with a beige band across lighter brown hindwings but still with the orange band and eyes on the forewing.








This was truly butterfly nirvana and we separated so each of us could concentrate on our own Scotch Argus to admire and photograph. I counted how many I saw as I slowly moved along the track but gave up, becoming too enthused and enthralled at this fantastic sight. Victory had been snatched from the jaws of defeat and the day was now rescued. Redemption was ours and we could not have picked a more perfect day to seek out the Scotch Argus as this butterfly truly loves sunshine and is very much dependent on it. 

When the sun shines the butterfly flies.The minute the sun goes in it ceases to fly and disappears deep into the grass or roosts in vegetation. There was no chance of that happening today.



I can honestly say that I have never seen so many butterflies in one short stretch of habitat as here at Smardale Gill. Apart from the Scotch Argus and Peacocks there were also many Red Admirals, all of them in prime condition and, in this year of their record invasion, of course there was a complement of Painted Ladys. Commas too were prominent and the occasional Meadow Brown provided a good comparison to the Scotch Argus. 


Red Admiral


Painted Lady

Comma
We walked on, hardly knowing where to look next and it was noticeable that the Scotch Argus was no longer fluttering about us. It appeared that they were confining themselves to just a short favoured stretch of the track. We walked on and still the Peacocks were everywhere. We must have seen hundreds by now.


Further on we came to the Smardale Viaduct which crosses the intruigingly named Scandal Beck that chuckled over its rocky bed many feet below. I always find these huge Victorian viaducts both beautiful and awe inspiring, evidencing, as they do, such great feats of engineering.  Just stand by one and look at its attractive appearance, built to last for years and always with a shape and construction that is both aesthetic and practical. Often, as in this particular viaduct, they are located in supremely beautiful countryside. Today the track across the viaduct was closed to walkers due to Health and Safety nonsense, a sign stating the railings were unsafe, not that anyone was taking any notice of that and just carried on walking over the viaduct regardless. No one fell off the viaduct or was killed by its falling masonry!


Smardale Gill Viaduct - now part of Smardale Gill National Nature Reserve
Crossing a stile and walking down a grass track that crossed a steep grassy slope to one side of the viaduct and beck we found yet more Scotch Argus, fluttering from scabious flower to scabious flower. By now we must have seen in excess of a hundred, probably many more, as a colony of this butterfly is often numbered in thousands of individuals.


The walk back was another Peacock extravaganza but it was noticeable that the Scotch Argus were nowhere to be seen now. As the sun increasingly shone on the track it had become very warm, too hot for the Scotch Argus, which had now sought the cool depths of the grass, burrowing down into the stems and stalks, out of the sun. It mattered not as we had achieved our purpose and the success of our visit to this wonderful reserve went far beyond expectation.

The last Scotch Argus I saw was an individual that flew onto a seeding head of Hogweed, and swiftly slid its upper wings below the lower wings to hide 'the eyes', relying on its dull colours to keep it camouflaged and safe from harm.


A very happy Peter -one more butterfly species ticked!
We had been on the reserve for almost two hours but it seemed to pass much faster. Reluctantly we departed Smardale Gill at three in the afternoon and were home at just before eight in the evening, listening on the way back south to the heroics of the England cricket team as they beat Australia in a thrilling Test Match.

All in all a very good day.