Friday, 4 March 2016

The North Ron Experience: A Subspecies View

A fantastic post by Hertfordshire / Cornwall birder Samuel Perfect who, alongside a few other young birders, spent a season on North Ronaldsay Bird Obs during 2015. For me, the following shows why birding is AMAZING - just when you thought you'd tackled ID of species, a whole new door of subspecific identification, migration and potential vagrancy opens. They may not be their own species, tickable etc. but for me, subspecific birding is some of the most exciting birding out there! I know one legendary frontier-breacher who would have loved this. Nice one, Sam - Jonnie F

The 2015 summer-winter season on North Ronaldsay was packed with activity.  A summary of events shared with a brilliant obs team can already be found on the NGB and NRBO blogs (here) so here’s an attempt to pad out the story from a different aspect. The subspecies we encountered were a mixture of stunning, confusing and above all, educational birds.  Here’re a few brief accounts of those that don’t often receive the attention they deserve.

Arctic Peregrine
On 7th September, George returned from his daily census with some record shots of a particularly interesting juv. Peregrine.  We spent a long time trying to extract as many features as possible out of the photos but it became apparent further field sightings would be necessary, preferably with the bird on the deck.  Some overdue genning up involved a look into a past NRBO report from 2012 which included a rather envious encounter with a stunning Arctic Peregrine. It soon became the obs team’s short-term mission to track down and solidify our suspicions that the pale capped bird the island was hosting might indeed also be an Arctic wanderer. The opportunity arose later the same day as Mark, George and I were outside Holland Gardens and in the late afternoon light it sailed past us.  My view of the bird was sadly silhouetted so most of what I have learnt from this particular bird derives from the photos. The extensive pale white/cream cap extends over the supercilium like a tiara, classic for Arctic Peregrine, the submoustachial stripe is narrow leaving large beige cheeks. It’s hard to be sure but the underside seems to show a beige cast and is much more finely marked with narrower spots and streaks on the chest compared to the other nominate birds also occurring on the island.

Probable Arctic Peregrine (George Gay)

Island Wren
It seemed each census route would be punctuated every now and then with either a burst of song or a not quite so small brown bird erupting from a dyke.  Almost as common was one of us volunteers repeatedly commenting on their notably larger size and darkness.  It took a while for me to appreciate the size difference of the island Wrens as there weren’t any nominate birds with which to compare them.  None the less, regular in the hand views (provided they didn’t wriggle out of my grip) revealed another brilliant opportunity to take a look at their chocolate brown ground colour, concolourous washed belly with less obvious transverse marks and larger bill.  Once back home in Hertfordshire I tried to find a Wren ASAP to compare the two whilst their appearance was fresh in my memory.  These had paler and yellow tinged underparts giving them a two-toned appearance with dark brown restricted to the upperparts.  With hindsight, they really did look different, cool!

iliacus and coburni Redwing
I remember the day well.  It was 15th October, I’d just left the obs and was cycling up towards Holland Gardens when a dark thrush appeared on the dyke to my right.  I slammed on the brakes, looked through my bins and only then did I recognised it was a Redwing.  It was a coburni!  A very generous present from my brother Ephraim (the Helm Thrushes ID guide) gave me the first inklings of hope that I might have a chance of finding one like it despite living in Hertfordshire, a rather uninspiring county for birding.  Perhaps, I thought, searching through the flocks of Redwings on my home patch might finally reveal something noteworthy like a coburni Redwing.  However, this never came to fruition and my interest was only rekindled with the arrival of Martin Garner’s Winter Challenge Series, this walked me through the simple steps required to pin down such a bird and thankfully the bird in front of me ticked all the right boxes.  Heavy streaked underparts with very little exposed white on the chest: check, comparatively dark legs: check, a tad larger size: check, glossy dark brown upperparts: check, ochre supercilium: check, flanks deep crimson red (not a warm orange hue): check.  Brilliant!  Over the next week or so Redwings became our main ringing query with triple figures trapped in Holland Gardens as they arrived and left the roost.  The switch from iliacus to coburni was noticeable from mid-October and alongside wing length measurements closely approaching and sometimes exceeding 126mm (the upper limit for iliacus) it became apparent just how different they were to iliacus which were processed with a refreshed appreciation for how much smaller, cleaner white and paler they were.

insulae and nivalis Snow Buntings
Perhaps one of my most treasured experiences was battling my way across the East Links golf course one November day in a severe headwind, lashed with sand, rain, salt spray and stumbling across a pair of Snow Buntings.  Numbers had dwindled since the impressive flocks of 400+ swirling around the Nether Linnay stubble fields but these deserved just as much attention and admiration as the pair couldn’t look more different from one another.  The first was a classic nivalis with pale rump, faint grey cast to the mantle, extensive white in the wing and yellow ochre tones restricted to the upperparts all highlighted just how dark its companion was.  The second was an Icelandic Snow Bunting (ssp. insulae) with rich earth brown upperparts extending across the flanks and smothering much of its head.  It was several shades darker with a darkened crown and ear covert patch.  An occasional wing stretch or flourish into the air revealed the restricted white to the secondaries and inner primary bases as well as the deep earth brown rump with some black uppertail covert centres.  The primary coverts were wholly black and the scapular centres were thin and black, indicative of a female bird.  I watched it for a full two hours and even convinced George to come and see it so that he might get some better photos.
nivalis Snow Bunting
insulae (left) and nivalis (right) Snow Bunts (phone pics)
insulae Snow Bunting

Siberian (tristis) and nominate (colybita) Chiffchaffs
A subject I’m sure many have already wrestled with and been frustrated by.  Fortunately, 3 years prior studying in Falmouth was an ideal opportunity to acquaint myself with Sibe Chiffs.  Sewage works are famously known to be great places for wintering phyloscs but it was great to see the same subspecies hopping over boulders and working their way through stunted bushes on the rocky coasts of North Ron as they first arrive in the country.  It always gives me a shock when I encounter a classic Sibe Chiff, yellow and green shades are restricted solely to the lower half, leaving the head, mantle and chest a foggy ghost.  Confusion arose with birds that closely resembled Sibe Chiffs showing some yellow/green tones creeping into the scaps and yellow in the front of the supercilium.  I would imagine they are of eastern origin but not quite in the range of tristis?
Chiffchaff probably of eastern origin (lack of green yellow tones around the upper half but creeping in on the scaps, also has chestnut tinged ear covs) (another phone pic responsible for saturating the colours somewhat, was in reality paler)

Siberian Chiffchaff (grey upper half, chestnut tinged ear covs and a faint wing bar)

argentatus Herring Gulls
With stormy weather large gulls would take refuge on the island, often congregating in their hundreds on the golf course or at the northern end of the island near the lighthouse.  Larus argentatus argentatus birds really are big, very often a few expletives would spill out of my mouth in astonishment when they glided past.  Yet again the island was playing host to a northern subspecies and it had all of us volunteers in awe.  Even the occasional Glaucs looked less beastly stood amongst a flock of ‘tatus!  Being from the south, I was not used to seeing Herring Gulls with such dark upperparts allowing a grey panel to seep through the underwing making it visible even from below, such was the power of the argentatus

Eurasian and Greenland White-fronted Geese
It was mid-November now and my fellow volunteers had all left so the island was left to Mark and I to cover.  A call from Mark to alert me of a flock of Greenland White-fronts heading south over the lighthouse gave me a head start in picking up the flock.  Unfortunately, they’d made their way directly offshore so, to me, they only appeared as distant grey geese sp..  Rather embarrassingly, I’d given the subspecies little attention as I had prioritised reading up on Snow Bunts instead and for lack of practice I’d forgotten most of the features necessary for separating Eurasian and Greenland birds.  Fortunately, I was given a second chance a month later to reacquaint myself with the Eurasian ssp.  Several hundred Eurasian White-fronts were assembled in the Reiselfelder, Munster (a brilliant wetland reserve in NW Germany) and thanks to excellent views of adult and juvenile birds in flight and feeding at close range I hope I’m equipped to right my regrets on my next visit to the North Ron to finally nail a Greenland White-front.
Juv and adult Eurasian White-fronts (Germany)

Adult Eurasian White-fronted Goose (Germany)
Pale-bellied Brent Goose
Yet another unfamiliar subspecies for me.  With the vast majority of birds being Dark-bellied in the south I can’t even recall if/when I last saw a Pale-bellied.  The dominant pale flanks, subtly different mantle colouration interspersed with pale fringing and the sharp contrast between the black throat and pale grey lower breast all pointed to another lesson learnt.

Dark and pale phase Arctic Skuas
This doesn’t concern subspecies but even so I’ve done some research to try and track down the exact meaning of phase and morph.  Apparently, they mean the same thing...  A little more digging revealed some good distribution maps showing the preference for darker birds to occur in the southern portion of their range (eg. Scotland) and pale birds to the north roughly separated by different behaviours and migration timings.  During my time on the island dark morph birds outnumber pale ones so I rarely saw pale morphs in action.  However, I remember with fondness the many evenings I spent at Twingness watching the sun set and dark morph Arctic Skuas (aka Scooty Allans) patrolling the rocky shore as the Black Guillemots (aka Tysties) returned with butterfish for their young.  Each dash to or from the bolder strewn shore to bring their valuable meal to eagerly waiting young birds spiked their adrenalin and rightly so as many would find themselves tangled in a dog fight with a brilliant pirate.
Adult Arctic Skua (dark morph)

Lesser and Mealy Redpoll
Not up to date with the taxonomy so not sure how long they’ll be remaining as species but here goes.  Being thrown in the deep end with redpolls has caused me to make lots of mistakes but I think I’ve learnt a bit in the process.  At first, many of the birds extracted from the nets at Holland Gardens resembled Lessers with suitably short wing lengths, buff bars etc.  However, with the emergence of fledgling birds later in the season, concerns were raised with respect to their wing lengths.  They suited Mealys on bios but on the surface appeared buff brown and classic Lessers.  So were the adults trapped earlier (that looked like Lessers) parents of the young which now fitted the bios of Mealy?  I’ve lost the plot.  Fortunately, once the confusion had died down and the birds moved on a fresh opportunity arrived.

We were in the middle of a fall with Blackbirds erupting from under boulders almost every step of the way, swirling flocks of Redwings and Fieldfares were the norm and there was a trickle of Skylarks, Bramblings and even the occasional Ring Ouzel.  Suddenly, a bright finch flushed a few steps in front of me, it was a Redpoll.  I took many notes on it but some latent blanks still puzzled me.  It had a sugar cube size white rump, a dominant cold appearance and a wash of straw tones about the face and chest just right for Coue’s.  However, modest flank streaking, a sizable black vent stripe and earthy brown scapular fringes not to mention its jizz dragged my hopes down to more realistic levels, it had to be a Mealy.  Fortunately, I was treated to good views as it crawled around in the long grass (making it appear significantly paler compared to views of it perched on a dyke against the pale sky which highlighted the darker streaking and deprived it of my initial Arctic impression.
Redpoll with a white rump, Mealy?

Mealy Redpolls? from August

Blue Fulmars
A major target species for me and also technically not a ssp. but a morph, anyhow.  From September we were treated to our first “blue” Fulmars passing the north end of the island, leaving the North Sea and travelling west into the Irish Sea.  Seabird passage was still productive beyond mid-November with some days heralding double figures of these “blues”.  Though technically a morph and not a subspecies, picking out a “blue” amongst the thousands of pale birds streaming past the island was great fun and as always educational.  First point, “blues” are variable with classic dark birds standing out well at long range with uniform slate blue underparts and upperparts.  Although we weren’t able to put a finger on the precise differences, “blue” Fulmars seemed to have a different flight jizz with noticeably kinked wings and a different flight style.  Paler birds with grey washed underparts concentrated around the breast and face also featured on several seawatches but I am unsure what to make of such birds and what might be responsible for these intermediate looks.

Northern Harrier
Our highlight of the season.  Yet again Mark’s hard work in the field was rewarded with a spectacular find, an adult male Northern Harrier!  This remained for the whole season and could well still be roaming the Orkneys undetected.  A picture speaks more than a thousand words so I’ll leave you with these to salivate over.  All I can add is watching it hunt a flock of 150+ Snow Buntings and a Yellow-browed Warbler hopping around at my side calling belongs to one of my very favourite experiences.

Bridled and Northern Guillemots
Once again, the challenge series came to the forefront.  Seawatching from North Ron, as expected, produced many more Bridled Guillemots than I am used to further south but this was also a good opportunity to grapple with more northerly breeding populations.  Although nothing the likes of a hypoborea happened, several birds with moderate black streaking angled across the flanks did pass the island in late autumn/early winter.  Although this might not mean much, this character does feature strongly in more northern Scottish populations perhaps Uria algaa algaa in its southern range.

Icelandic Meadow Pipit
Back in 2012 at the first Spurn Migration Festival, Clive McKay invited me to join him at the Sheepfields to trap migrant Mipits on their southward migration as they became concentrated through the funnel shaped landmass before crossing the Humber.  He introduced me to the subtle differences in plumage tones of autumn birds.  Warm brown and yellow in the mantle and breast were typical of British birds but cold white ground colours to the chest and much reduced warmth to the upperparts with olive green tones and a longer wing length supported his hypothesis that these might well be Icelandic Meadow Pipits.

From August North Ron experienced a surge in Mipit activity, triple figures would sometimes take to the sky when traversing a field and although the majority evaded close scrutiny, on-the-deck views revealed some similar looking birds to those that I was fortunate to handle three years ago at Spurn.  Cold underparts and upperparts on some birds made them stand out a little but unfortunately few birds on migration were trapped to record the all-important bios so a crucial piece of information went missing from the puzzle.

Are they littoralis Rock Pipits?
They surely have to be littoralis was what went through my head when I saw them.  At the start of the autumn season only one or two birds were known to be on the island so the small arrival that occurred from late September must have originated from elsewhere.  With A. p. petrosus restricted largely to the British Isles and strong NE winds originating out of Scandinavia carrying with them continental birds such as White Wags, Barred Warblers, Ickys and Wrynecks it seemed likely the Rock Pipits might be coming from a similar direction.  Obviously, this hunch is near impossible to prove as littoralis in their winter plumage are apparently impossible to separate in the field.  Some reading from Ian McKerchar (The Logicality of littoralis) might provide a glimmer of hope with regards to lingering birds in early spring that might begin to show signs of pinkish on the breast, emergence of clean slate grey tones on the mantle and reduced streaking on the chest as well as some indication that some might be separable in winter too.

blythi Lesser Whitethroat
My first encounter with a blythi Lesser Whitethroat was November 2014.  My friend Dan Chaney and I were at Stithians Res and a very late Lesser Whitethroat had just appeared in the pine trees.  It was a challenge to get the necessary tail shots, recordings and all round views but we successfully managed all three.  Nearly a year later and with a bit more reading accomplished, I found myself a little more prepared when an interesting Lesser Whitethroat cropped up in the nets at Holland Gardens.  T6 had a thin dark wedge on the inner web reaching 2/3 of its length and T5 had the characteristically large white wedge indicative of blythi.  Mark and I were laden with many more birds in need of processing so some quick photos and feather samples were taken before releasing the bird.  Several months later an email came through, with confirmation from Martin Collinson on its DNA, it was indeed a blythi!
blythi Lesser Whitethroat

And the rest…
There were so many more avenues available to explore, we only touched on discussing Greenland Wheatears when the odd nominate bird was trapped in the Heligoland traps.  I did my best to separate White and Pied Wags but hardly even took a closer look for Icelandic Blackwits, Continental Chaffinches or track down the Northern Bullfinch that George was lucky enough to have fly past him.  There was simply too much on all of our plates even to grasp the opportunity to trap the potential samamisicus Redstart Espen found with a noticeable pale wing panel.  Even before I arrived, the obs team had been graced with perhaps the rarest bird of the year, Todd’s Canada Goose, another subspecies conundrum.

A sad fact I had to deal with whilst on the island is the commonplace of death.  Overhead wires and wind turbines claimed many bird’s lives often severing their wing before leaving them to a slow and painful death.  It really tugged at the heart strings to see injured Ruffs, Curlews and gulls struggling their way across fields but besides all this death, it was a brilliant opportunity to study the birds close up.  Dead 1st CY Common Gulls were what I sought after most.  I’d turn each bird over onto its back and try and learn something, would there be a bird with a considerably paler underwing and delicately marked fringes to the greater underwing covs and axillaries?  Could there be a heinei?  This is all far out of my depths so I simply took a close look at the underwings and photographed them for future reference.  In hindsight I should also have looked more closely at the Ringed Plovers for darker arctic birds, search through the Dunlins for alpina, schinzii and arctica or at the Goldcrests for grey naped Continental birds.
1st CY Common Gull underwing

Goldcrest with a grey nape?

For anyone hoping to volunteer at North Ron there are endless opportunities to discover and learn from what the island throws at you.  A massive thanks goes to Kevin Woodbridge (Owner), Alison Duncan (Warden) and Mark and Fleur Warren (Assistant Wardens) and all the volunteers I met during my time on the island (Stephen Rutt, George Gay, Gavin Woodbridge, Peter Butler, Jonny Scragg, Espen Quinto-Ashman and Molly Laban) for patiently answering endless questions, making the obs feel like a second home and giving me the opportunity to do what I love most, go birding!

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