Perishing for a Pallas's 6th January 2022

Yesterday, Gareth, who normally spends much of his birding time at the appropriately named Grimsbury Reservoir in Banbury decided to give himself a treat and visit sites in Oxfordshire with a larger selection of birds. Maybe that is a little unfair as 'Grimbo' has on a number of occasions produced some very nice birds.

One of the sites Gareth chose to visit on his away day was Abingdon Sewage Treatment Works where he found two Siberian Chiffchaffs amongst the twenty plus Common Chiffchaffs, that eke out a winter existence by taking advantage of the plentiful supply of insects found around the work's filter beds. Normally the find of the Siberian Chiffchaffs would be considered a good enough result but it was eclipsed and how, by his truly sensational find of a Pallas's Leaf Warbler in the hedgerow bordering the northern side of the works. A county mega, it was the first ever for Oxfordshire no less.

Pallas's Leaf Warblers breed in southern Siberia, northern Mongolia, northeast and central China, southeast Tibet and northeast India. In winter some only descend to lower elevations within their breeding range whilst others migrate to winter in southeastern China, Burma, northern Thailand and northern Indochina. It is a rare but annual vagrant to western Europe including Great Britain but wintering birds in Britain are very unusual.

News and photos duly appeared on the Oxon Birding Forum WhatsApp Group in mid afternoon. As was to be expected much comment followed, as the rest of us envied Gareth his find and made frantic plans to get to the sewage works first thing in the morning.

The big question was whether the warbler was just a passing vagrant or was it toughing out the winter in the trees and bushes that surround the sewage works. There was only one way to find out and that was to go and see.

Mark (P) called me that evening and we arranged to meet at my house at 7am next morning and drive to Abingdon in tandem, as both of us had other commitments in different directions later in the morning. Overnight there was a hard frost, and in the still dark morning the frost had turned everything to a glittering white glaze in the street lights and was to make driving on the rural roads around where we live decidedly dodgy. It was bitterly cold too - minus 4.5 degrees and I was never more glad of the efficiency of my car's heater.

An hour's drive found us parking by the rugby club playing field and taking Peep-o-Day Lane that skirts the playing field and leads to the track that forms the northern boundary of the sewage works. This track borders a fence that guards a somewhat ragged hedgeline of bushes and trees and the filter beds beyond.

Turning the corner from the lane and onto the track we found we were not the first, as many of Oxonbirds finest were already lined along the track, intently scrutinising the hedge, even as the sun had yet to rise and any birds in the low light of a dawn not long risen, were just silhouettes against the lightening sky.

More and more of my fellow Oxonbirders arrived. It was a veritable roll call of familiar faces, every one of us keen to add this new species to our county list.

Many Common Chiffchaffs were passing through the skeletal branches and twigs of the hedge and as the light improved so plumage detail could be seen but there was no sign of any pale Siberian Chiffchaffs,  only the olive buff tones of Common Chiffchaffs. Behind us were taller trees, conifers and bare deciduous trees and these also had a lesser complement of Common Chiffchaffs and the odd Goldcrest too.

For almost two hours I stood getting progressively colder, not so much demoralised, more a little downhearted. My toes had begun to feel very numb and so too my finger tips despite thick gloves and socks.I had only another hour before I needed to leave and I was resigned to failure or maybe coming back tomorrow if the bird was seen after I had left. Some had already departed, having work commitments to go to while others gave in to the cold. 

As often happens at twitches if a bird does not show, after a certain time the intensity of observation gives way to chatting and other diversions and if you are not careful there comes a time when hardly anyone is looking for the bird in question.There are after all, only so many chiffchaffs you can watch before the will to live grows faint! 

A small group near me thought they saw 'something' in the conifers and went in further to scan the trees. Then came the moment everyone was secretly hoping for. It came from the far end of the track. Pete, with exemplary dedication  had continued searching for the warbler and had been rewarded with a sighting of the elusive and tiny Siberian gem.

A concerted surge of Oxfordshire's birding humanity headed for the far end of the track. A phalanx of anxiety racked birders rounded the corner expectantly and found Pete, who described where he had seen the warbler but inevitably, with such a constantly restless bird, it had already gone. After a few minutes others  went further along to a copse of mature trees, many of them alders, and the alert went up again as the hyperactive warbler was discovered in the tops of the trees there.

Gathered in a throng we watched enthralled as the tiny bird zipped around the top of an alder, searching the tiny twigs for sustenance, having a brief dispute with a Blue Tit and causing me some confusion as to which  bird was which until they separated.

It all happened so fast but I can recall seeing an amalgam of moss green upperparts, yellow wing bars and stripes on its head which left no dispute as to its identity.Tiny, like a cross between a Goldcrest and a Yellow browed Warbler it flew at speed across and above us to flick around the top of another alder. I thought it impossible to get it in the camera as it was so frenziedly active, rarely still for a moment. I preferred to concentrate on watching it, as wherever one sees a Pallas's Warbler it is always a notable event. However there came a time when it looked like I might get an image.Why not? I raised the camera. Focus and - it was gone. Another try and for  a brief two seconds I could see it relatively unobscured and fired a ten frame burst from my camera. Hit or miss. But by chance I got two images.Not great but they would do.

The warbler flew once more, further into the trees but despite the many eyes searching it remained undiscovered but at least almost everyone present had seen it.

I walked back to my car with Paul. It has been a long time since I saw him. It was pleasing to be in the company of and share this unique experience with so many people I knew and liked.

PS I went back on Sunday and after a long wait saw the PLW very well and for extended periods in the afternoon. There was quite a big crowd and the bright sun shining directly into the lens made photography difficult