A Hume's Warbler in Norfolk 19th January 2017

Friday was predicted to be cold, very cold but sunny. My attention had been drawn to a rare vagrant, a Hume's Leaf Warbler, spending the last fourteen days in and around an isolated single storey home called Shangri-la-Chalet at Waxham on the Norfolk coast.

This particular Hume's Leaf Warbler had first been found on 5th January when it had been identified as a Yellow browed Warbler, this species being a close congener, but was re-identified as a Hume's Leaf Warbler the next day. Hume's Leaf Warbler is a bit of a birder's bird and it is hardly surprising that the original finder plumped for the relatively commoner Yellow browed Warbler, as this species, another vagrant from the east, has of late years been occurring in increasing numbers in Britain in autumn and isolated individuals have even been found in winter, such as in Sussex in February 2012 and even in my own county of Oxfordshire on 3rd January this year.

The name Hume's Leaf Warbler commemorates Allan Octavian Hume, a British civil servant and ornithologist who was based in India. There have been one hundred and thirty nine Hume's Leaf Warblers identified in Britain up to the end of 2016, occuring at an average rate of five per year and increasing. The peak of arrivals have been in late October and especially November, later than Yellow browed Warblers and predominantly on the east coast. Not including this bird, ten have been found in Britain in January. The shortest stay was of just fourteen days and the longest one, found on 2nd January 1995 at Great Yarmouth, again in Norfolk, remained for 117 days. Another was found at Fairlop Waters on the Essex/London boundary on 11th January 2004 which remained until the 25th of April and even commenced singing towards the end of its stay. The same bird was thought to have been seen singing at the Brent Reservoir in London on 1st of May that year.

It is always a source of amazement to me that such a tiny scrap of life weighing no more than a few grammes can tough it out in a British winter, especially one such as we are currently experiencing. Hume's Leaf Warbler is one of the smallest of a group of tiny warblers that are predominantly green above and dull white below, colloquially grouped as 'leaf warblers', and it is only slightly larger than a Goldcrest. Its tendency for vagrancy into western Europe in late autumn means, when it does arrive here, it is at least 3000km west of its normal wintering areas. Its normal breeding range encompasses mountain forests from the Altai Mountains to western Mongolia, southwards through the Tien Shan and Pamirs to northeast Afghanistan, the northwestern Himalayas and the mountains of northwest China, reaching altitudes of 3500m above sea level. They migrate in autumn over the Himalayas to spend the winter in northern India, ranging east to western Bengal and southern Afghanistan.

Hume's Leaf Warbler has only comparatively recently been split into a separate species (1997) from the very similar looking Yellow browed Warbler, based on differences in morphology, song and call and molecular characteristics. Compared to a Yellow browed Warbler its plumage is a duller, subdued version of the brighter coloured Yellow browed Warbler. Seen in the field it looks a greyer green on its upperparts and dull greyish white on its underparts and it has only one prominent wing bar, again duller and buff rather than yellow, and there is just an impression of a second, shorter wing bar.  Its legs and bill are also darker than those of a Yellow browed Warbler.

By far the best way to identify it, however, is to hear its call which is markedly different from that of a Yellow browed Warbler, being a strong disyllabic tsu-weet and shorter and lower in pitch than that of a Yellow browed Warbler.

To have the opportunity to hopefully see my third Hume's Leaf Warbler in Britain and in the fair county of Norfolk, on a sunny day in winter, was just too good an opportunity to forgo so I gave Moth, one of my birding friends a call, as he does not work on a Friday, and suggested a jaunt to Norfolk which he readily accepted.

At 6.30 on a cold dark morning in Oxfordshire we set a course for the east and Norfolk. Being a weekday we were soon amongst the craziness of commuting traffic but with just a few minor hold ups we were soon traversing the roads of Nelson's  County in bright sunshine. The sun at this time of year was so low in the sky that it was blinding and necessitated the donning of my Raybans but all was well as we headed for Waxham. We turned off the helter skelter of the main road to Great Yarmouth and found ourselves winding a course on quieter roads through the hinterland of this part of Norfolk. Leaving one final small village, the Norfolk I love materialised, as we found ourselves driving through the wide open spaces of Horsey Levels with the gentle rise of the dunes way off to our right and dank, cold looking fallow fields of plough or grass to our left. 

The ditches around the fields were marked out by stands of beige coloured, stiff reed stems acting almost as a fence or blinds, one such reed filled ditch shielding our road. We stopped at a gap created by a field gate to admire a herd of well over a hundred Whooper Swans with a few Mute Swans amongst them, their plumage enhanced to almost dazzling whiteness by the bright sun and then, further down the road, another large field of grass contained a huge flock of Pink footed Geese, so many that the green of the grass was almost hidden by their close packed, clay brown bodies.We stopped and immediately a thousand necks shot up as the whole flock became alert. In situations like this it would be wonderful, although admittedly fanciful, to be able to communicate our good intentions, that they were quite safe and would not be shot at but some of my fellow humans still find entertainment by killing such beautiful birds so they are right to be wary. Their's is already a dangerous existence made unnecessarily worse by human selfishness in trying to kill them in the name of relaxation and sport. They surely have as much right to inhabit this world as do we.

With such philosophical meanderings being mulled over in my head we proceeded past Horsey Mill to wend our way down a long, straight and empty road below huge open skies of blue, following the Satnav's directions. I could see what looked very much like Shangri-la-Chalet off to our right and we duly turned up a very narrow, wet and muddy lane, passing an old disused church, to park in a sea of mud and puddles.We could see a small huddle of birders walking up a footpath that passed by the fence guarding the large garden of the upmarket looking chalet. The birders were obviously intent on following what was presumably the Hume's Leaf Warbler.

The Footpath running past the garden of Shangri-la-Chalet
then turning at a right angle in front of the distant bushes

We donned wellingtons and warm clothing, hung cameras and bins from our bodies and set off in pursuit of the birders. Anything less like Shangri La at this moment would be hard to imagine as although sunny it was bitterly cold as the wind from the northwest came across a large fallow field unhindered, to blow through the bare twigs of the hedgerows and over the landscape of winter.

The warbler was feeding below and in front of the bushes and trees on the bank

The chalet itself looked like a holiday home and was extensive with a large garden around which ran a footpath both to the back and front. We followed the footpath to where four or five birders were standing looking across to the back of the garden at some bushes and small trees growing on a sloping bank that continued east towards Horsey. I assumed they had seen the warbler fly to where they were looking but it soon became apparent that no one knew where the warbler was and they were just standing and staring hopefully. A couple of Blackbirds were plucking berries from an ivied stump, a Wren flew across the garden and a large skein of Pink footed Geese straggled across the sky in the distance as we waited.

Half an hour passed as I became increasingly frustrated and downcast at the complete lack of anything that would give us hope of finding the warbler. Yesterday it had been reported as 'showing well' so why was it not so today? A photographer, toting a huge lens came along the footpath from where it turned at a right angle and ran under the bank towards Horsey. I enquired whether he had seen the warbler and he replied that yes he had but it was being very elusive and hard to see let alone photograph. He suggested we try where he had just walked from as the warbler seemed to prefer there to the immediate surrounds of Shangri-la-Chalet.

A man with a lurcher then walked around the path behind the back of the chalet. We eventually got talking and he was a local birder and informed us that we were looking in the wrong place and would not see the warbler where we were standing. He told us the warbler was hard to locate and the best strategy was to wait for it to call as then you could at least have an approximate idea of its location. He told us that it mainly fed very low to the ground and even on it, underneath the bright green leaves of emerging Alexanders, an umbelliferous plant which carpeted the bank under the small trees and bushes. As a consequence the warbler was very hard to see and follow as it never really stopped moving for an instant and being so tiny was often hidden below the leaves. I had imagined the warbler would be feeding higher in trees or bushes and not on or near to the ground, so at least we could forget about any trees or bushes and concentrate on the Alexanders.

Note the pale indistinct central crown stripe which can
sometimes be seen on this species and its close cousin
the Yellow browed Warbler

We followed him along the footpath as we all looked and listened for the warbler and then we parted. Moth and myself wandered slightly disconsolately, it has to be said, back and fore for the next forty or so minutes wistfully looking at a bright green carpet of emerging Alexanders that were most definitely, currently not hiding a Hume's Leaf Warbler.

At some juncture I turned to look across the fallow field and back to where the path went past the chalet and saw a huddle of birders and some walkers who had just passed us clustered around the man with the lurcher. All were looking up into a tree that overhung the footpath. It was obvious they were looking at the warbler judging by their excited demeanour.

Moth and myself hurried back along the few hundred metres of footpath to join them and looking up into the canopy of the tree I saw the tiny outline of the warbler flitting amongst the close packed twigs and branches of the tree. It was only a shape and silhouette as it constantly moved around and looking from below all you could see was its off white undersides. I was anxious for Moth to see it as it would be a lifer for him but it was very elusive and the views even if you got one could hardly be called satisfactory. Then it flew a long way back to the bank with the Alexanders. We followed, just five of us now plus the man with the lurcher. We demurred to him as this was his local territory so we respected his rights to lead and dutifully followed. The warbler, when we relocated it, was feeding on or very low to the ground but for the most part was invisible and only showed itself very briefly when it noticed us and flew away in alarm, uttering its distinctive and diagnostic call, before disappearing under the Alexanders once again. We followed as this process was regularly repeated. For long periods it was out of view and we sometimes thought we may have missed it moving to another area but then it would re-appear from where it had disappeared and fly off, calling. This went on for some time as it worked its way along the bank and then something changed.

I have no clue as to why or for what reason but the warbler appeared to decide that it no longer viewed us as a threat and commenced to ignore our presence and slowly and methodically work its way back along the bank, no longer indulging in an escape flight from one point to another. We quietly followed as it periodically appeared and disappeared amongst the Alexander leaves, scuttling and hopping about on the sandy earth, methodically searching the undersides of the leaves, nooks and crannies in the sandy soil, under branches and through the dead stems and twiggy detritus strewn on the bank. Its change in behaviour made it much easier to locate and you could actually follow its progress through the leaves now. Getting a picture was still a lottery as it was virtually constantly on the move, never still for more than a few seconds, but because it was methodically moving in one direction we could anticipate where it would emerge into an area that was almost bare of leaves, more exposed and that was not obscured by twigs and the low branches of the trees and bushes growing on the bank. Somehow, utilising this strategy, we both managed to get passable images. 

What it was finding to eat I have no idea, presumably ants, minute invertebrates, spider's eggs and other  such minutiae but it certainly seemed a tough existence on the cold, wind exposed bank although it was obviously finding enough to survive on, at least up to now.

We watched and followed it for another thirty minutes and then departed leaving just one person tracking its progress through the leaves. These were easily the best views I have had of a Hume's Leaf Warbler and I just hope it manages to keep body and soul together through these winter months and provides as much delight to other birders who come to see it, as it did for us today.

Sadly there was no sign of the warbler on Saturday or since.