Port Meadow Peregrines

The Port Meadow flood partially froze overnight which is always interesting for birding as the waterfowl tend to cluster quite tightly on the remaining areas of water. This morning it attracted a pair of Peregrines which hunted continually over the ice for around half an hour - shamelessly filled an SD card before my hands and feet went numb and I had to go and warm up in a cafe. Beautiful light and it was also snowing at points - the temperature didn't get above zero for most of the day. Really put the Olympus through its paces, a challenge keeping focused on the birds and shooting with the correct exposure as they stooped across different backgrounds. The birds stayed pretty distant, so most of these images are heavy crops, but I'm pleased with the results.

Back from Hong Kong - Kittiwakes!

Seven of the fourteen Kittiwakes seen today!

I had thought that in lieu of some excellent patch bird my next blog post would be a report of my Hong Kong trip, which is still in preparations. Therefore, this will be a relatively quick one, just to cover the exceptional events of this morning!

I arrived back from Hong Kong on Sunday and have had a relatively quiet couple of days on the patch, especially as I've had quite a bit of work to catch up on. It was quite a surprise on Tuesday morning to open the curtains and find it snowing rather heavily - in these situations I can only ever think about the possibility of cold weather movement and also thought it might be quite scenic for photos, so I decided to drive to Port Meadow before heading to Wytham for work afterwards. During the journey the snow had turned to sleet and as I arrived it mostly cleared - the patch was looking very aesthetic indeed and the cold snap didn't seem to have had too much of an effect on the wintering birds, with the waterfowl and wagtails being quite lively and feeding on the flood. A few flocks of Golden Plover wheeled overhead and Snipe were particularly conspicuous - they are quite sensitive to snow/ice on the ground.

 

Pied Wagtail

Shoveler and Wigeon on the flood

I had seen reports on Birdguides of Kittiwakes at Stanford and Pitsford Reservoirs in Northamptonshire yesterday evening, so I actually had this species on my mind as I walked along to Burgess Field gate - it would be a patch tick for me after missing two in April 2023. There were a small number of Black-headed Gulls loafing on the floods but a quick check through them failed to reveal anything out of the ordinary - likewise, there didn't seem to be any Chiffchaffs to look through along the ditch, so I decided to just take a few photos and then head to work.

As I began walking back along the path a group of small gulls flew in from the east and began circling high above the floods. I thought I'd better check them and the first bird I saw through my bins, a bit below the rest of the flock, was an adult Kittiwake! I quickly raised the camera to take some record shots and one of the photos I've included below, completely unedited apart from cropping, just to show how gloomy it was.

Initial views of the Kittiwake - unedited

At this point I assumed this must be a lone adult with Black-headed Gulls or something, so I was amazed to check through the other birds in the flock and find that they were all Kittiwakes! Fourteen in total - eleven adults and three first-year birds. The birds were still circling over the floods and I could even hear them calling as I began taking more photos - the gloomy conditions weren't great for photography and the birds quite distant but I managed to get some acceptable results.

This moulting adult came quite close

I thought at one point that they were going to land but after a few minutes they swirled round and began flying north, at which point I lost them over Wolvercote.

Wytham hill in the background

The best photographic opportunities came as they headed off north as they weren't right overhead - unfortunately I never managed to get all fourteen in one frame!

Brilliant when a plan comes together. This record seems to have been part of a wider influx of Kittiwakes inland, with birds also reported in Gloucestershire, Worcestershire, Yorkshire and London this morning. The Port Meadow flock seems to have been the largest group, although twelve were also seen at Beddington Farmlands.

These Kittiwakes become my 156th patch bird and only the second I've found in Oxfordshire, after two at Farmoor on 28th October 2020.

Geese in the snow

Back to blogging and patch update

Port Meadow stalwart Adam Hartley photographing a rainbow on a birdless morning

With the slow demise of Twitter and procrastinating over the inevitable move to Bluesky I've posted very little on social media recently - yet I've still found myself wanting to write about birding. I'd almost forgotten about the existence of this blog (which began as bit of a Covid lockdown project) which is a shame as its longer format is perfect for patch updates rather than just the odd tweet with a photo. We already have the Port Meadow blog but I've always been slightly hesitant to post on there - for one it's Adam's creation, and his blogging style is rather different to mine, but also I'd prefer to write mostly about birds that I've seen and found personally (and sometimes go into substantial detail about these birds). Combined with wanting to occasionally report on trips away from Port Meadow, the time seems ripe for returning to this blog, and hence I'll try and commit to posting semi-regularly, perhaps two or three times a month depending on whether there's actually some birds to write about.

Until mid-September I was away from Oxford, having spent the summer after handing in my DPhil thesis doing various nice bird-related things - short trips abroad to Lithuania (helping to catch and ring Greenish Warblers for a friend's project) and Germany (ringing and GPS tagging juvenile Lesser Black-backed Gulls). Following this I stayed at Portland and Copeland in late August/early September, and whilst getting stuck into observatory life and experiencing some fantastic days of overhead migration, seawatching and ringing, I saw very little in the way of good birds, other than some expected early autumn scarcities (Wryneck and Great/Cory's Shearwaters on Portland, and a couple of Sabine's Gulls on Copeland).

Wryneck, Portland Bill - much more elusive than this photo suggests!

After a month spent at these birding hotspots (I say this - can Copeland really be counted as a birding hotspot?) it was a brutal return to the realities of Oxon birding, where most days in the field end with seeing nothing at all! My ears had clearly been tuned in a bit given that I picked up a flyover Tree Pipit heading south over Otmoor on 6th September, which I was pleased with as they remain relatively uncommon as a passage migrant in Oxfordshire. When I got back Port Meadow had yet to flood for the winter, and was still dry grassland - hence my efforts were focused mainly on ringing in Burgess field, with a couple of days catching good numbers of migrants (mostly Chiffchaffs, Blackcaps and Meadow Pipits). Oddities included a Reed Warbler (surprisingly scarce on the patch although this is the second caught by the ringing group this year) and a "capless" Blackcap on 18th September, which has already done the rounds of social media so I won't go into further detail other than including a photo of it here - it seems to be a known aberration that can occasionally occur.

Note the incomplete eye-ring and greater covert break - the bird also had very plain undertail coverts

With the lack of a gull roost on Port Meadow I decided to make a few trips to Farmoor Reservoir on nice evenings - visibility and lack of wind are very important when the birds are hundreds of metres away. On 22nd September I saw a Black Tern and Little Gull with Ben Sheldon as well as one or two Caspian Gulls regularly in the roost over the couple of weeks. Three Great White Egrets circling the northern basin (F1) and a Rock Pipit on 29th September were also notable. Wader passage for me was limited to a few Dunlin, Ringed Plovers and Common Sandpipers. 

This 1cy Caspian Gull has been hanging round Farmoor quite a lot during the day, affording some fantastic photographic opportunities

Heavy rain at the end of September caused a rapid rise in water levels and the meadow went from bone dry to "lake mode" in little over a week - probably the earliest it has ever flooded to this extent in the eight years that I've been going there. The floods immediately attracted waterfowl, gulls and a couple of Great White Egrets. When the floods are this large viewing from Burgess Field gate is very difficult as the birds are hundreds of metres away, so I usually cycle along the Thames path and watch from the other side of the river - which also has the advantage of having the light behind you in the evening.

From this...

...to this, in about a week

1st October looked like good conditions for the roost so I headed down from Godstow and began waiting for gulls to fly into on the flood - I had arrived a bit early.  At around 18:20 I noticed a very dark 2cy Lesser Black-backed Gull sitting directly opposite me on the water - alarm bells began ringing as it looked perfect for a Baltic Gull! The mantle had a mix of very dark adult-type feathers and worn second-generation feathers giving it a "scaly" appearance which I've come to associate with fuscus and some intermedius - combined with the plain tertials, unstreaked white head and yellow bill with black tip it looked almost exactly like the birds that I had seen in 2021 at Appleford. I put the news out as a probable and was just getting my phone into position to digiscope it when it flew - slight panic as I reoriented the scope but then got a good view of an almost pure white underwing, and, crucially, a set of wing feathers that had obviously been replaced months ago - the pale tips to the secondaries looked very tatty and compared with the other Lesser Black-backed Gulls the primaries were clearly more worn. It eventually settled with other gulls on an "island" at the north end of the flood and I was able to take some ropey digiscoped images. Sadly the bird flew before Adam arrived - although I managed to pick out a 1cy Caspian Gull at dusk which was a minor consolation.

Collage of digiscoped images in the gloom

My main concern was whether fuscus could be identified at all this late in the year, since most other 2cy Lesser Black-backed Gulls would have completed their primary moult and hence the criteria used to easily separate them in spring and summer are less applicable. However, since many fuscus replace their juvenile primaries, secondaries and rectrices on the wintering grounds, these second-generation feathers will be much older than the equivalent feathers on graellsii/intermedius, as these would have only just been replaced over summer. I am happy that I got good enough views to assess this feature and I think it is also visible in the photos of the open wing. The absolute clincher would be seeing two, or even three generations of primaries - a moult pattern unknown in "western" Lesser Black-backed Gulls, but shown by some of the most advanced fuscus. It was unclear from the photos and from viewing in the field whether this was the case, as the moult limit in the inner primaries can be very subtle and is suspended prior to migration, so there are no feather gaps in the wing to look for.

Overall, having shown photos to Ian Lewington and then circulating them on Twitter, the feedback has been positive - whether it is worth submitting to BBRC is a different matter. For me, finally getting one on Port Meadow has been a real grip back after being unable to clinch what was almost certainly a distant flyover on 3rd June - Ian also had a 2cy fuscus at Didcot on 22nd August which is possibly a different bird from the extent of tertial wear. 

Near misses for me this year - a fuscus seen by Ian Lewington at Didcot whilst I was at Portland and a probable flyover I had on Port Meadow in June

This autumn has seen one of the best arrivals of Yellow-browed Warblers in the last few years, particularly inland, and with the discovery of two birds in Oxfordshire already (one at Lye Valley and another at Farmoor Reservoir) I had high hopes for the patch. On 9th October I was walking back from a fairly mediocre solo ringing session when I heard what I thought was a Yellow-browed Warbler call coming from somewhere in the allotments - although I wasn't 100% sure over the rabble of dog walkers coming along the path. Stopping just outside Burgess Field gate, I waited for perhaps another 10 seconds before hearing a single call again, quite clear but fairly distant. Unfortunately I had to hurry off for a work commitment so couldn't stay to look for it any longer, so I put the news out and Adam was out looking for it after lunch to no avail. I was back down in the evening for the roost and also had no luck (although I did find a 1cy Mediterranean Gull). I had initially urged some caution with regards to adding it to the year list based off of a brief heard-only record, and I think my nervousness was exacerbated by the fact that this would be a patch tick - having missed a widely-twitched bird in the Trap Grounds in September 2022. However, I eventually had some sense talked into me by Adam in that this was a perfectly acceptable record even without visual validation, so I'm happy to include it as a patch tick, albeit quite an unsatisfying one!

For the last few years parts of the southern end of the meadow have been left un-mowed, which this year have attracted up to three Stonechats. Formerly a passage migrant through Burgess Field in October, we've recently been getting some overwintering in this area. I also heard a Cetti's Warbler singing from the ditch next to Walton Well car park on 17th October which is the first I've actually recorded on meadow itself, although it was dubiously on my patch list before from birds along the Castle Mill stream and at King's Lock.

Phil Barnett found a Whooper Swan on the morning of the 22nd October, a less than annual patch bird that I was keen to catch up with so I hurried down in my lunch break and met Adam and Phil on the meadow. The bird was very distant, feeding on the grass with geese on the opposite shoreline - a flock which bizarrely also included a feral Ross' Goose, another species for the Port Meadow "plastic" list!

Whooper Swan from the riverbank - it ended up staying for three days

Ross' Goose - this bird has been around the county for a while and usually hangs out at Otmoor

We were walking back towards Walton Well Street and examining some Stonechats when I heard the distinctive short, buzzy call of a Rock/Water Pipit overheard - the bird had come up from the grass where some Meadow Pipits were feeding and flown north over the floods. I had a brief and distant view of it through bins which didn't reveal much except that it looked grey and somewhat clean underneath - unfortunately Adam and Phil didn't get onto the bird. I can't pretend that I would be able to distinguish the calls of Rock and Water Pipit with any reliability so it will have to be left as that species pair. I have seen a Water Pipit on the patch before (a bird found by Phil in October 2022) but Rock Pipit would be a patch tick for me, so slightly gutted - might still be time left this autumn to get another.

Aside from the swan, the only other interesting wildfowl specimen has been this strange duck which after a bit of head scratching seems to be a Wigeon x Gadwall hybrid

A return visit to Farmoor that evening with Ben and visiting birder Milosz Cousens produced one of the best roosts I've experienced at the reservoir - four Caspian Gulls (two 2cy, a 4cy and an adult), over twenty Yellow-legged Gulls, and a 2cy Mediterranean Gull . Three of the Caspian Gulls were showing superbly on the smaller reservoir, where the gulls typically roost much closer to the causeway, so we got some fantastic views. A Rock Pipit was calling along the causeway and a Peregrine flew through and buzzed the gulls in the near darkness just as we were leaving.

On 25th October I had an unexpected patch tick in the form of a flyover Yellowhammer - the first vismig highlight of the autumn. I confess that upon initially hearing it I couldn't place the rather anonymous "tsit" flight call (despite being a bit out of context there was no excuse really, given that for the last couple of years I've been involved with surveying the winter finch/bunting feeding stations in the Cotswolds which regularly attract hundreds of Yellowhammers) - however as it got closer I realised that the call was coming from a large bunting-shaped bird flying east quite high over the southern end of the meadow, at which point the penny dropped. Despite Yellowhammers wintering barely a mile or two away, this is only the second recent record for the patch following another flyover seen by Nick Boyd on 11th October 2020 - some discussion with Mick Cunningham seems to indicate that they are relatively uncommon on vismig even in areas where they breed/winter nearby.

One of the regular Great White Egrets

Fuelled by the promise of good vismig I continued with my morning walks - in the past I've usually visited in the evenings for the roost, but I've realised that the best chance of adding to my patch list is probably chance flyovers in the mornings - birds like Ring Ouzel, Crossbill, and Hawfinch to name a few. The latter was something that I was particularly hoping for as vismiggers across the country were reporting a modest influx. On 28th October I headed out very early (the clocks had just gone back), arriving in the pre dawn gloom. Initially the conditions didn't seem promising, with few birds going over - a couple of Siskin, a Redpoll, and two Black-tailed Godwits circling the floods. I was standing by Burgess Field gate trying to decide whether it was worth persevering when I heard a metallic "srrriii" call somewhere above me - brain whirred into gear, I hadn't heard them for quite a few years but knew it had to be a Hawfinch, began madly looking around for it - then it emerged from above the Burgess Field tree line, surprisingly low, barely ten metres above me! Had phenomenal views right over my head as it powered south-west, an absolutely fantastic patch tick. I gave it another half an hour but by this point was getting quite cold so decided to head into town to start work for the day. Just as I was walking back I spotted two large finches flying over the floods - a quick check with bins and yes, also Hawfinches, much higher up and apparently silent. Three in one morning far exceeded my expectations, and next time I vowed to bring a camera - I had just bought a new mirrorless Olympus setup (switching over from a Canon 7D Mark II) and was quite keen to test it.

The report of Hawfinches even managed to tempt Adam out the next couple of mornings and sure enough on 1st November we were standing photographing an adult Mediterranean Gull that briefly dropped onto the floods when I once again heard the unmistakeable call of a Hawfinch - shortly drowned out by me yelling "hawfinch!!!" and Adam yelling "where???". I saw a speck bombing over us so swung the camera up and hoped that it would lock on - in the couple seconds it was visible I took 66 photos using the pre-capture function! Adam thankfully had got onto the bird, his second patch Hawfinch after seeing some with Ollie over Burgess Field way back in 2020. My elation turned to horror when examining the photos on the camera - I had obviously failed to adjust the exposure compensation from shooting a white bird against the dark floods to a dark bird against the white sky, and hence all 66 photos were just of black blobs! Clearly a skill issue with the new camera, although shooting in RAW meant that I was able to recover a surprising amount of detail and whilst the photo will win no prizes it's a serviceable record shot - I never thought I would be able to get photos of flyovers like this on Port Meadow.

Hawfinch photo straight out of the camera...

...and the edited record shot!

Since the Hawfinches the patch has been relatively quiet, although the floods have pulled in a few waders - a Curlew, low numbers of Dunlin, a couple of Redshank and a Ruff. In previous autumns the Golden Plover flock has attracted two American Golden Plovers (before my time sadly), Pectoral Sandpiper and Dotterel in 2021, and regular Grey Plovers, so plenty of potential at this time of year.

Record short of a distant Curlew on 5th November - impressed with the cropping potential of the Olympus

A misty morning - four Dunlin circling with the Golden Plover flock

I'll be away from Oxford next week for a Hong Kong trip - always an uneasy feeling leaving the patch for an extended period of time, but hopefully the birding will make up for that. I anticipate that the next blog post will be a trip report, and one of the main aims of the trip will be photography.

The Baltic Gulls at Appleford

Baltic Gull - field sketch

This year, I've developed a bit of an obsession with mid-summer gull watching. Right in the doldrums between the last Caspian Gulls departing and the first juvenile Yellow-legged Gulls arriving. There's only one bird on my mind here - Baltic Gull.

The nominate form of Lesser Black-backed Gull, Larus fuscus fuscus, breeds on the fringes of the Baltic Sea, northern Scandinavia and northwest Russia. It is really quite a different beast to the British graellsii and Western Europe intermedius. It takes only three years for it to reach maturity, as opposed to four years in most other large gulls. It is also a very long-distance migrant, travelling from the breeding colonies to winter in Africa, some 6-7000km south. This is probably the selective pressure that has driven adaptations such as accelerated moult and long wings in comparison to the other two subspecies of Lesser Black-backed Gull. Baltic Gulls usually migrate through Eastern Europe and hence their status in Western Europe is unclear, although it is likely that they are not particularly common as their migration does not follow the Western coast.

There seems to be a particular apathy amongst birders towards the occurrence of Baltic Gull in Britain - it's tarred by the "subspecies only" brush, and candidate small, elongated, dark-mantled Lesser Black-backed Gulls are recorded fairly regularly. For me, however, simply stringing an intermedius isn't enough - I need to be certain. Since the publication of Lars Jonsson's original paper in Birding World, it has been found that the variation in the moult of graellsii and intermedius is far greater than initially thought. This has led rarities committees to consider second summers and adults essentially impossible to separate from intermedius - so currently, there are only two types of Baltic Gull sighting that are acceptable from a vagrant perspective: ringed adults from "pure" colonies, and first-summer birds from May-August. Because of these rather strict criteria, there have only been 12 records of Baltic Gull accepted by the BBRC up until the end of 2019 - although it is certainly an annual migrant rather than the mega vagrant that these numbers would suggest.

I don't actually agree with this assessment myself and I think a combination of moult and jizz in these older age classes would be extremely supportive of a positive Baltic Gull identification, especially in small female fuscus where the structure is really quite far removed from intermedius - but it is what it is, and therefore in my quest to find an acceptable fuscus I would have to focus on ringed adults and first-summers. And let's face it - field-identifiable first-summers are much more interesting...

So, what to look for in a first-summer Baltic Gull?

I have summarised the differences between Baltic Gull L.f. fuscus and Lesser Black-Backed Gull L.f. graellsii/intermedius in the plates below. I produced these illustrations digitally using Adobe Photoshop. Please click the plate and "open in a new tab" to view full size!

Plate 1

Structure

Baltic Gull averages slightly smaller than Western Lesser Black-backed Gull, although this is often not immediately apparent in the field due to the huge variability in size demonstrated by graellsii/intermedius. What is usually obvious is the very long primary projection and attenuated rear end, which is accentuated by the differences in moult described later. Often appears quite short-legged and small-headed, but again variable.

Bill

First-summer fuscus typically have a much more mature-looking bill than contemporary graellsii/intermedius, with most of the bill base being pale yellow/pink with some residual black markings at the tip. Some individuals even have a hint of red gonys beginning to develop. In contrast, first-summer graellsii/intermedius tend to have a dark bill, although some will have the same pale base to the bill that fuscus shows. Therefore, I would say that birds which have an all-dark bill are unlikely to be fuscus, but birds with a pale base to the bill are not necessarily fuscus. Bill structure seems variable enough as to overlap completely with graellsii/intermedius.

Plumage

Baltic Gulls tend to have a very distinctive mantle colour, being a rich dark brown colour. This is also noticeable on adults, where the brown wash across the mantle immediately serves to distinguish fuscus from similarly dark-mantled intermedius, which usually have a more slaty tone.

The second-generation scapular feathers are plain brown, with pale edges when worn, producing a distinctive scaly look. There will sometimes be a dark line following the shaft of the feather, but no perpendicular anchor marks. Second-generation feathers in graellsii/intermedius are very variable but many have a Herring Gull-like pattern of anchors on dark grey feathers which should immediately rule out fuscus. Throughout summer, Baltic gulls will replace their scapulars with new third generation feathers which are very dark black-brown, almost as dark as the black mantle of adults. This should be noticeably darker than any feathers present in the mantle of graellsii/intermedius.

The coverts are plain brown with slightly paler worn fringes in old second-generation feathers, with new black-brown third-generation feathers beginning to poke through in late summer. Any kind of strong barring on the greater coverts seems to be a bad sign for a candidate fuscus. The tertials are dark centred with broad white tips, lacking any kind of subterminal barring. Birds with fuscus-type moult displaying covert/tertial barring are likely to be hybrids with intermedius.

Body/underpart feathers are variable in fuscus, but average whiter than graellsii/intermedius of the same age. The head feathers are white with with streaking around the eye and on the nape. In comparison, many graellsii/intermedius will be quite heavily streaked in their first-summer. A white underwing has been mooted as a good identifying feature for fuscus, especially when juvenile, but from looking at a large number of photos I thunk this feature is as variable as any other large gull. The tail pattern ranges from a band with barring leading up the rump, to almost completely dark retrices. The rump feathers tend to be white, rather than barred.

Moult

It is in their moult strategy that Baltic Gull deviates most from graellsii/intermedius. Due to being a three-year gull, with accelerated moult strategy resulting from long-distance migration, the extent of moult can be used to safely distinguish a large proportion of fuscus in a western European context. Before departing their wintering grounds in Africa, first-winter fuscus will replace at least eight, and usually all ten primaries, as well as all their secondaries and tail feathers. This complete post-juvenile moult is usually finished by April. In comparison, graellsii and intermedius tend to start their primary moult in May, and therefore will be undergoing this moult throughout the whole of summer. Because of this, those few fuscus that end up in Western Europe in May and July will have primaries that look distinctly blacker and fresher than all other Lesser Black-backed gulls in the area. The second-generation primaries and secondaries differ slightly from the juvenile feathers, with the secondaries having broad white tips, the inner primaries having small white fringes to the tips and with P10 sometimes having a small white mirror.

The pattern of moult in the first-summer Baltic Gull illustrated in Plate 1 is typical of many individuals in early summer (May-July), with all primaries replaced with fresh second-generation feathers on the wintering grounds. It is these individuals which are identifiable as Baltic gulls, as some slower-moulting birds will have arrested their moult halfway through replacing their primaries and would therefore not be separable from graellsii/intermedius. Altenburg (2011) states that any bird with more than eight new primaries should be a Baltic Gull - this is illustrated in Plate 2 with an individual that has retained a worn, juvenile P10. In early summer, Baltic Gulls will have no wing moult, which immediately distinguishes them from graellsii/intermedius. 

Plate 2

As summer progresses, graellsii and intermedius will start their primary moult, which invites confusion with fuscus. This is especially the case in late summer when fuscus will start its third wave of primary moult, replacing their inner primaries with fresh third-generation feathers with broad white tips. In some rare cases, they will still have retained their old P9/P10 from arrested moult prior to migration, hence showing three generations of feathers in the wing - a moult pattern known as Staffelmauser (Plate 3). Whilst this places them almost a year ahead of their Western counterparts, both forms will be in active moult and it can be challenging to assess the exact age of the primaries at distance. In flight, the juvenile primaries of graellsii/intermedius will typically look pale brown and heavily abraded, whilst the second-generation primaries of fuscus will still appear pretty black, just slightly more worn than the fresh third-generation primaries poking through. The broad white tips to the third-generation primaries of fuscus should also be obvious given good photographs. July is typically the month in which graellsii/intermedius shows an incomplete tail - once they have replaced all retrices this can no longer be used as a feature to separate them from fuscus.

Plate 3

The difficulty in assessing primary moult is especially apparent when birds are standing with a closed wing - since some intermedius will have replaced a lot of their primaries by mid-August (in some cases up to P8) simply looking for birds with fresh black primaries in late summer is futile. However, even on the closed wing, there are some clues that can be used. Baltic Gulls will still have a much longer primary projection as they will have a full set of outer primaries. In contrast, these feathers in graellsii/intermedius will still be in active moult, regrowing P9-10, and therefore these birds will look pretty truncated at the rear despite the primaries being fresh and black. This is illustrated in Plate 4 - fuscus will have about six primary tips visible beyond the tertials (P5-10) whilst graellsii/intermedius will have at most four, with the outer primary being P8 and P9/P10 regrowing behind it. Comparison with the other plumage features described above means that fuscus can still be identified with care through late summer.

Plate 4

Getting into September, graellsii/intermedius will have completed their primary moult and fuscus will have suspended its moult halfway through renewing its primaries to third-generation. At this point it becomes extremely difficult to assess primary moult and the window for identifying first-summer fuscus in the field closes.

So to summarise, the key features for safely identifying first-summer Baltic Gull in a Western European context in May-August are:

1. At least eight first-generation (juvenile) primaries replaced with second-generation, or in late summer, third-generation feathers. If P9-10 are retained first-generation feathers, this will be from arrested moult.
2. Full set of second-generation secondaries.
3. Full set of second-generation retrices (tail feathers).
4. Dark black-brown third-generation scapulars and coverts in the mantle.
5. Lack of strong barring in the coverts and tertials, with most feathers being plain brown.

Other indicative features include:

1. Pale-based bill with black markings at tip.
2. Elongated structure.
3. Whitish head and underparts.

Armed with this knowledge I began searching. After a few weeks of visiting the pit, and staring at hundreds of photos, the "moment" finally happened on 1st July. Surprisingly, it wasn't the primaries which initially drew my attention to the bird, as they were hidden behind another gull. Instead, it was the rich, brown, mahogany-toned mantle, with plain scapulars and coverts and the odd darker feather poking through. The head was white and the beak was pale yellow with a black tip. After about half a minute of watching this bird it flicked its wings slightly and for a split second its primaries were visible - tar black triangles that cut straight through the heat haze and hayfever. It really was one of those "you'll know it if you see it" moments - I had doubted my ability to actually pick this out at distance, and had been umming and ahing over the dubiously darker primaries of a couple of candidate birds in previous weeks.

In slight disbelief I waited a minute for it to do it again before phoning Ian Lewington, who luckily lives only a few minutes away and regularly watches the gulls on the landfill and gravel pit. Unfortunately it was at this point that the bird decided to go to sleep and so when Ian arrived it was displaying precisely no diagnostic features. It was also incredibly distant in amongst the furthest group of gulls some 300m away on the opposite side of the pit, and I was beginning to doubt what I had seen. A few agonising minutes passed before eventually, it woke up again and stretched its wings high above its head, revealing a full set of fresh primaries and secondaries with no obvious moult break - sealing the deal for me. Ian luckily managed to capture this on video, which was immensely helpful as this was, of course, the one day that I neglected to bring my phone scope adapter, and was really struggling to get good images just by holding my phone to the eyepiece.

After putting the news out and appreciating the bird for a bit longer, Ian suggested that we walk round to the bend in the road where it might be slightly closer. The vegetation had grown up quite high since my last visit and I struggled to peer over it - Ian, being taller and with a straight-through scope, had no such issues and quickly picked out the bird preening on the spit. After 10 minutes it took off and began flying around the pit, revealing a fully replaced tail with a diffuse band matching the intense black colour of the primaries, and with fresh white tips to each feather. It then steadily flew high north along with a few other gulls that were beginning to depart the pit, perhaps heading to Radley Lakes to roost. 

I saw this bird again on 13th July, where it showed reasonably well at a similar distance. Note how small-headed the fuscus looks in comparison to the graellsii/intermedius behind it. Interestingly, stills from the video footage of it taking off show a slight gap at the base of the primaries.

Then, on 6th August, I saw this individual a third time, and it had clearly started its third wave of primary moult, replacing P1-2 with fresh third-generation feathers with larger white tips. P3 was missing and the second-generation P4-10 still looked black and fresh enough for this feature to still be used to pick out the Baltic Gull despite it being in primary moult. This accelerated primary moult fits perfectly with the identification as fuscus - now, it is almost a year ahead of its graellsii/intermedius counterparts.

It transpires that Roger Wyatt had seen this individual on the Spit Pit (a pool near Didcot Landfill south of the main gravel pit) in the morning and had sent Ian a range of superb images. Many thanks to Roger for allowing me to reproduce them here - an upgrade on my mediocre digiscoping for sure! These photos also reveal that the bird is currently undergoing extensive covert moult, having lost a large number of greater coverts on the right wing. Note the difference in tip pattern between the third- and second-generation primaries.

Since then, this particular individual has become regular on the pit in the evening and several local birders have managed catch up with it. At the time of writing it was last seen on 13th August, so it has remained in the area for 43 days.

On 28th July I found a second individual. I had panned over a sleeping gull a few times, and noted that it had very black scapulars. Being partially obscured and with its head tucked in, I wasn't sure whether it was simply a small second-summer Great Black-backed Gull. After a while it woke up and revealed a slim, yellow/pinkish-based bill, and a really tatty, moth-eaten white head - clearly in moult, and recalling Jonsson's illustrations in his 1998 paper. The visible primaries were tar-black - success! 

This individual was far more worn, having tatty white edges to the scapulars and coverts. I find this "scaly" look really distinctive, with the combination of relatively plain, dark-brown/black centred feathers with pale worn edges looking completely unlike other Lesser Black-backed Gulls. Its structure was much less extreme than the previous individual. Upon examination of the video footage of it flapping its wings, it was clear that P10 was an old, juvenile feather, being pale brown with an abraded tip. The tail was fully replaced, and had a much thinner black band than Bird 1. 

On 7th August Ian found a third bird - sadly, I was out of county that day and therefore did not see the bird myself, but luckily the bird showed very well and Ian was able to take a series of photos which I have reproduced here. It is in a similar state of moult to Bird 1. However, it is slightly more advanced in its scapular moult and its bill pattern is different, with a hint of red gonys beginning to come through.

I saw the bird myself a couple of days later and amazingly it was on the pit at the same time as the "original" Baltic gull!

As if three Baltic gulls wasn't enough, Ian sent me a photo that Roger Wyatt had taken of a first-summer Lesser Black-backed gull on the Spit Pit a couple of weeks ago. It looks like the perfect candidate fuscus, and clearly different to the previous three birds on the basis of bird markings, and moulted covert and scapular pattern. Sadly, this is the only photo, and I'm not sure if it's possible to clinch the age of the primaries from it. To me, they do look jet-black, and the tip of P7 on the left wing (visible above where the right wing tip bisects the left wing primaries) looks rounded. P10 looks a bit ragged on both wings. I would have liked a flight shot and views of the tail... but I am sure it is one!

So probably four different first-summer Baltic Gulls at Appleford in the space of a month - really quite unprecedented when I set out searching in at the beginning of summer. These also become the first confirmed Oxfordshire records after a few potential adults and a juvenile in the past. I have no idea if they're actually as regular as this suggests - some far better gull-watchers than me have spent several years searching before finding one. I would be interested to see if this pattern is repeated next year, or whether this is a one-off mini "influx" -  I suspect the latter is unlikely as it's not been correlated with other birds reported from other sites in the UK. Really rewarding either way and good to try and clarify the status of Baltic Gull in the UK. Maybe in a few years, we'll be finding them as regularly as Caspian Gulls...