Sunday, 8 January 2023

Candidate 3cy American Herring Gull, Seton

This strikingly marked imm “Herring Gull” leapt out at me on the Seton Burn, 15:28hrs on 3/12/22. Mantle a shade lighter than neighbours, with a hint of pastel blue, but massively contrasting heavy nape and flank streaking extending to the belly. These are all good initial clues to identification of an American Herring Gull, but given the variability in so many aspects of immature gull plumages a careful analysis is needed to establish the required suite of features to confirm ID. Fortunately with 90s of video recorded, as well as 40+ photos, many features could be checked, though views of the inner wing were limited to when it was partially open for preening (viewing from side and rear), while the tail was seen well but not fully spread.

The first essential step is to establish the age. Though nearly all plumage features, and bare parts, might give clues to age, the critical ones are the primary pattern, in particular whether the feathers have been replaced with third cycle feathers which are pale grey (not mixed with brownish) in the inner primaries and, critically, showing proper white “tips” to the feathers (big in inner wing and progressively smaller to outermost). While the image quality is not great, there is no doubt that these features can be seen – careful scrolling through the video enabled to establish that the feather with the dark subterminal mark is P4, thus P5 has a big white tip (also just visible in closed wing), P6 a quite small one and then tiny tips out to both P9 and P10. This is a typical pattern for 3cy American (European Herrings are essentially the same but tend to have more extensive white tips in outer primaries, especially in argentatus). Further support for the age is seen in terms of the moult step and greyer replaced primary (3) and secondary (1) greater coverts, as well the mainly white under/upper tail coverts, rump and vent, the white underwing and the good overall progression of moult with the scapulars completely replaced in pale grey, along with the upper tertials, though apart from coverts moult none of the latter on their own are definitive (but also American Herrings, especially from the East coast, tend to be more retarded in appearance compared to European, i.e. having on average more brown feathers in the scapulars).

Now coming to the identification, the critical features are the black or very dark brown colours in the tail, the secondary bar and the bases of the tertials. The tail is certainly quite striking, appearing entirely a solid black colour, save for a faint white subterminal band (which is expected, even in birds with otherwise solidly black tails). Careful analysis of all the footage, including the video, shows that it is otherwise certainly entirely black, even in T6 up to the position where the retrices disappear into the tail coverts, with no sign of the white in the base of the tail edge (which would be expected even in a 2cy Herring Gull). In addition the secondary bar also is consistently blackish (visible in rear views below the coverts when wing drops while preening, and even in the underwing when wing raised while preening), and the bases of the unmoulted tertials also appear as either blackish or very dark brown, depending on the angle. A good supporting feature is the contrasting dark brown greater coverts bar (with one replaced greyer feather as noted) which is also typical for 3cy American.

Further reflecting on this proposed identification and information in the literature, it is known that an all dark tail is characteristic of American and these critical features of dark blackish markings in tail, secondaries and tertials, when viewed in conjunction with the heavy nape and flank marking and strong contrast in the mantle, therefore all point towards identification as American. In their seminal identification paper, Lonergan & Mullarney (2004) highlight the significance of tail pattern in particular:
"While there is extensive overlap in the tail patterns of second-winter smithsonianus and European Herring Gulls, it seems that even the most extreme examples of the latter usually show a narrow wedge (widest at the base) or ‘sliver’ of white along the outer edge to the tail (shown by some smithsonianus too but a definite lack of white edges may be significant).

This example of a 2cy European Herring with an unusually black tail still shows obvious white in the edge of closed tail: https://chrisgibbins-gullsbirds.blogspot.com/2011/03/herring-gulls-variability-in-first-and.html. The same is true for this example for a 3cy with an unusually dark tail: https://www.flickr.com/photos/johnswildlifephotos/24854194186

In fact by 3cy most European birds have much less black, quite often just faint residual marks (e.g. http://www.gull-research.org/hg/hg3cy/3cynov06.html), while American can retain a nearly entirely black tail (e.g. http://gull-research.org/smithsonianus/smith3cy/3cydec002.html, http://gull-research.org/smithsonianus/smith3cy/3cynov02.html). Immature gulls are of course hugely variable in appearance, but while it is very true that some immature American Herring Gulls can therefore not be definitively identified, extensive dark in the tail at 3cy age should be diagnostic.

Next, on tertials, Lonergan & Mullarney (2004) state:
"Many show extensive, sharply defined, solid-black/blackish-brown markings towards the bases of some tertials, usually, the middle and/or outer feathers. Such definite, blackish markings as in the best-marked smithsonianus are seldom, if ever matched by European Herring Gulls.

Finally, for the body, Lonergan & Mullarney (2004) state:
"The dark head, neck and breast-markings of third-winter types average heavier and more blotchy than in European Herring Gulls, especially argentatus, on which these markings tend to be paler and less extensive. On the most heavily marked birds, the density of dark spotting, especially on the hindneck and breast, is strikingly different from anything usually seen in Europe but a few ‘dark’ sub-adult argenteus can be similar".

To conclude, while the resolution in the images obtained falls a way short of what would be ideal, I believe it is sufficient to see key features on this individual which should permit an indicative identification. Indeed had it been lacking in some of those features, in particular the very heavily marked nape and flanks, there is a good chance I would never have noticed it in the first place. Looking ahead, such an individual should remain pretty distinctive in appearence at least while aged 4cy, and probably beyond, so the hope now is that it can be seen again – a main purpose of this short account is to alert people to be on the lookout for further sightings, whether here or further afield…

References

  • Adriaens, P. & Mactavish, B. (2004) “Identification of adult American Herring Gull”, Dutch Birding 26: 151-179
  • Dubois, P.J. (1997) “Identification of North American Herring Gull”, Brit. Birds 90:314-324
  • Howell, S.N.G. & Dunn, J. (2007) “Gulls of the Americas”, ch. 25, Peterson Reference Guides, Houghton Mifflin Harcourt
  • Lonergan, P. & Mullarney, K. (2004) “Identification of American Herring Gull in a western European context”, Dutch Birding 26: 1-35 [Presented and illustrated on the Gull Research Organisation website: http://gull-research.org/smithsonianus/1cyoct.html]
  • Mullarney, K. (1990) “American Herring Gulls in Ireland”, Birding World 3:96-100
  • Olsen, K.M. & Larsson, H. (2004) “Gulls of Europe, Asia and North America”, Helm
  • Van Duivendijk, N. (2010) “Advanced Bird ID guide, The Western Palearctic”, New Holland

Friday, 6 January 2023

Seton/Gosford patch and ring reading 2022

More patch stats and brief ring reading summary. Altogether rather fewer excursions and fewer records submitted for patch this year but these mainly due to more time in work early and late in the year when too dark to get out when home – overall total of birds counted was actually higher than last year at 244k. This was influenced in part by substantially more Sandwich Terns with an earlier arrival, though that in turn perhaps as breeding colonies were abandoned due to HPAI bird flu. Otherwise totals for most species were rather down in line with reduced visits, though Shag were also significantly increased (and a new day record of 395 on 28/11 was both remarkable and rather concerning – previous high count here was 40 back in Aug-Sep 2012!). 148 species recorded for 3rd year running, glass ceiling?
Nevertheless 5 more (potential) bird additions to my patch list, though 2 (American Golden Plover and Pallid Swift) were found by others and another 2 are/would be subject to acceptance by rarities committees (Caspian Gull, American Herring Gull, see below).  Great to get a set of 7 species of tern including the second Gull-billed Tern for the patch (video) (after first on Seton Burn on 12 June 2016, BBRC accepted) – and also only the second record for Lothian if accepted.   

Also very pleasing to finally get a confirmed Wood Sandpiper which flew up from the west ponds on Seton golf course on morning of 14 May, only seen in flight but I happened to have my voice recorder on, so calls were recorded confirming ID.  Early the same morning a Tree Pipit W calling and a lovely view of a Cuckoo in flight along the beach made it one of the best spring vismig days on patch (counts) and lucky I could get out early.  Another personal favourite was the 1st-sum Little Gull, “Patch”, which was seen irregularly from mid June to early September, once on the upper beach with the BHGs at dusk feeding on sand hoppers.

Some bird pics, large gulls, small gulls, other birds!

On mammals, the remarkable occurrence of two presumed Sowerby’s Beaked Whale in Gosford shallows on 26 July, but as a deep water squid-feeding species it did not look good and as I rather feared news then followed of a live stranding with one that died on the Moray Firth on 10 August. Remarkably the species is named after James Sowerby, an English naturalist and artist, who first described them from a skull obtained from a male that had stranded in the Moray Firth in 1800. Sightings from land remain extremely rare but there have now been a number of strandings in East Lothian over the last few years (Gullane 2019, Brunstane & Gosford 2020, Port Seton 2021).

Highlights over the garden were two Green Sands (including first diurnal migrant), another nocturnal calling Quail, another migrant Tree Pipit and several more gallinules and waders, plus Barn Owl and Whooper Swan (garden blog). Wall butterfly was new for the garden, along with the first Hummingbird Hawkmoth *in the house*!

c. 8k bits of litter cleared again, mostly chucked from car windows - c. 30% cans, 30% plastic bottles, 10% disposable cups, 30% other stuff, with upsurge in Nitrous Oxide usage with new trend for big aluminium cylinders which are soda cream rechargers along with the little canisters; £35 a shot, good that some have escaped the credit crunch:

Also increasing numbers of so called "disposable" vapes, all leaking battery waste and potentially some nicotine into the environment, I would like to know who decided these would be branded "disposable" and why our politicians did not/have not intervened to do something about it, believed now to be 1.3M "thrown away" each week (BBC news article). A welcome campaign on this by @GreenAlliance and some impressive work by @LessWasteLaura in Dundee, also some useful commentary on the current issues for recycling, but here East Lothian Council does not collect them for recycling (assuming they are "electrical items"), so even if I dismantle them it seems they would not take the batteries? This is just crazy and something needs to be done! [PS - welcome update]

Having put a lot of commentary on last year’s patch blog (and 2021 ring reading blog) I thought I would just add a few comments on three different topics here, bird flu, disturbance and rare bird recording:

HPAI (Bird flu) 

This is a great tragedy and the impact on local breeding seabirds has been nothing short of catastrophe. But surprisingly it has not yet led to significant decreases in birds recorded locally, indeed counts of some were significantly increased, albeit for unwelcome reasons. Of particular interest were the Sandwich Terns which apparently arrived earlier and in bigger numbers than usual, see comparison chart for last three years: 

Oddly, I can trace no info on the historical status of this important tern roost at Gosford Sands – no records in our local recorder database and having consulted with both previous wardens of Aberlady Bay, who had counted terns “round the corner” in the Bay, neither were aware of it. I find it hard to believe it had not existed and must confess that I had also overlooked it until COVID struck, forcing me to get onto my bike and go out on a more regular basis.

We also expected a spate of ring recoveries from dead terns but after an initial recovery of Blackness-ringed Sandwich Tern white-E63 at Alnmouth (link) the next reports were all positive for live birds, with red-UVK reaching Port Elizabeth, Eastern Cape, within 50 days of leaving here, and having been seen at Rhyl along the way (link).  

We also had a remarkable series of new records from colonies in the north of Ireland, with 3 out of 4 being first summers (having previously had only one such in 1400 ring reads from east coast colonies (link).  First summers normally remain south in the wintering range but perhaps there are regional differences with this, not yet clear if it is a known phenomenon.

One of those from Donegal was blue-631, ringed on a nest there on 4/6/22 – after being seen here at Port Seton at 13:34hrs on 9 August it was logged at Rhos Point, North Wales at 07:30hrs on 10 August – 162 miles in 18 hours! 

To conclude, a few shots of the Gosford tern roost, viewing from the upper shore at low tide at dusk on 26 & 27 September, the last few birds gathered pre-migration, first photo 19:20hrs, rest 19:30-19:35hrs (sunset 19:01hrs): 

Dog walker disturbance 

After some rather heated exchanges about disturbance by dogs on Lothian Birdwatch I made more of an effort to engage with locals on this topic.  We have a sign at the “Red Burn” bridge (aka the “Seton Burn” to birders) which politely requests locals to keep dogs under control on parts of the shore

This particularly highlights the zone at Long Craigs where the swans hang out, as they are fed. Problem is, birds don’t respect these boundaries – the traditional roost site for Curlew when tide is out is by the pipe between the bridge and Seton Sands – and if undisturbed small gulls often gather on the Sands in large numbers (up to several thousand, also peak of 4100 Herring Gulls by Burn on 14/9/21). But for some the gathering of birds there is too much to resist and they make a beeline for them and sometimes encourage their dogs to chase them (see photos in thread linked above). 

I had an interesting exchange with a local on 22 December – there were 49 Curlew roosting by the pipe that day along with 4 feeding Bar-tailed Godwits and many small gulls on the Sands (including Med Gulls red-PKT5 and yellow-AS.AT) (complete list) and tide was fairly well in.  As owner passed I asked politely “excuse me, did you see the sign at the bridge?” – owner blanked me and took his dog straight out to water line where I watching him encouraging it to run at the gulls:
I presumed that was in response to my query. So on his return I said “I only asked a polite question” – he said he had not been able to hear me but after I explained again he said, yes he sees the sign every day, but it is only a recommendation, not a requirement, and that the beach is a public space and his dog is big and needs exercise!  I do sympathise with the dog needing exercise and in that case I can understand why he does not want it on a lead, but there must be other ways of doing that other than encouraging it to chase birds?

Rarity claims

On another topic entirely, I thought I would put down some thoughts on the minefield of rare bird claims, having struggled with a couple this year (and also had one submission rejected). I must admit that 20 years ago I was pretty naïve on this and made a couple of mistakes in making hasty claims that I still regret (including not a Ring-billed Gull) – not that I had any intention of making a false claim but just that at the time of disseminating the “news” I had not established sufficient proof in support of the claim (in any case none were ever submitted).  Having been lucky enough to find a few slightly rarer birds in the last few years (but nearly all at sunset in fading light!) I have had some fresh perspectives on this “problem”.

Case in point, the Gull-billed Tern found at 20:55hrs on 17 May – pretty distant and sunset approaching 21:22hrs (image above); to me I felt I had been able to discern all the key features and personally I had absolutely no doubt what it must be – but was there enough evidence in the poor images if it had not appeared again? I thought about alerting locals but it is a tricky one – you make a claim, even with provisos, and then cannot back it up, which can be awkward. Having pondered it overnight and carefully assessed the images my confidence had increased, so I decided to put out the news as “interesting tern” so that others could then be alert to check. There is always a risk that people might interpret the disseminated message as “you found a bird which you are not certain about and/or trying to string into a rarity with insufficient evidence?!” Fortunately in this case the problem was quickly resolved (though subject to approval by BBRC) when the bird duly reappeared at same time the following day, and again the day after that (with 2 twitchers!) – but had it not done so I very much doubt whether they would have accepted it on the basis on my poor distant images, even though they at least hinted at the key features. This would have been a really messy one in making a claim of such a rarity (potential second for Lothian), only for it to be rejected.

The next one was actually found after sunset, on 12 October, but a bird which I locked on to as a Caspian Gull from the instant I saw it – my social media feed being stuffed with them. But then you immediately start thinking “can you really prove it is not some kind of an aberrant, or even an odd looking Yellow-legged”, etc., all as you are battling to get sufficient images in fading light (bird on shore for 22 minutes before flying to roost, but often partially obscured behind other birds). This one was less stressful as I was confident to put it straight onto Twitter as “interesting LWHG” and within minutes there was support flowing in for ID as Caspian (also subject to approval by SBRC).

The biggest one remains outstanding and in principle a more difficult ID, but after careful research I believe that this bird on the Burn at sunset on 3 December shows all the required features needed for 3cy American Herring Gull, which I felt it looked like when watching it. In this case feedback was virtually absent and news services understandably ignored it; unlike the various rarities mentioned above, for this species it is widely acknowledged that not all individuals may be identified conclusively to species, given the overlap with (European) Herring Gull particularly beyond 1st and 2nd-winter (e.g. Lonergan & Mullarney, 2004). Confidence in identification all depends on the particular features shown, and general scepticism is to be expected, particularly with such an extreme rarity (2 accepted east coast records, in Norfolk and Suffolk, both found by same gull man, Pete Wilson). Moreover, even with birds seen well in Iceland questions of purity may arise, and the views of current would probably not be sufficient to exclude any possibility of hybrid influence, though there is nothing to particularly suggest that. Nevertheless, as a potentially significant record I have analysed and documented it in detail (40+ photos and 90 seconds of video in seven chunks all with clues to the critical features, full details of primary tips, tertial pattern, tail markings, etc) as well as doing extensive research in the relevant literature. There are no obvious counter features and everything examined has only solidified my view that the original ID must indeed have been correct - hence have also done a separate blog outlining the key features in the identification so others can be alert - and of course feedback comments welcome. And who knows, it may be back?

This brings me to my final comments on the deceptively simple question of “when (not) to submit?”; I certainly wrestled with submitting my claimed White-billed Diver of 17 April 2021, well aware I had far from any proof in the images alone for acceptance (just a dot slightly right of centre in the clear sea above) and bird was a great range (but not beyond the distance at which we routinely record common species on the sea in good visibility) – hence potentially putting the committee “in an awkward position” (a phrase I have often heard). I fully accepted the outcome which was understandable given the range, and may well have voted against it myself, had I been on the other side of the fence (and I do recall reading case of a committee member voting again their own record mentioned on the BRFC (Bird Records Committee Forum), the US local recorders list, so that idea is not unheard of!).

But should I therefore have submitted it, given this was the likely outcome and what I was fully expecting? I can understand that some would think not, and it would have saved everyone a lot of precious time, but on the other hand while acknowledging that it would be unreasonable to deny I could ever have been mistaken, based on my live observation I did have a very strong internal confidence that it was one, i.e. the stated ID was correct, and the logical consequence of that to me is that it should correctly be documented as such. If it stands on the record as “not proven” then to me, so be it, arguably this might be rather better than giving the impression that “a claim was made but the observer later had doubts” or even “a speculative claim was made”. Though in some contexts, e.g. after researching literature, grounds might come to light as a basis for doubts (e.g. GND can have extremely pale bills and sometimes hold them angled upwards) – when I also think an honest commentary should be given. In the current instance it so happened that a Great Northern was present off same site the following morning and briefly claimed (by a third party) as same before being withdrawn, showing how tricky this pair might be for the unwary and the importance of being strictly objective.

Looking back on my 2009 “not a Ring-billed Gull” I can now see that (at the least the bird I managed to photograph!) it is 100% a Common Gull, albeit with some slight variations in appearance on the typical, and I’m happy to now say that and learn from those features. To conclude, initial qualified claims and considered rarity committee submissions are rather different things. I certainly don’t believe submissions should be made “on spec” and I respect the position held by many who would, I know, never submit without anticipating that acceptance would be a formality. But personally I tend towards an alternative view that, while fully recognising your own limits and the often non-negligible uncertainties in identification from multiple sources, if you nevertheless have sufficient personal confidence in a record, and have been cautiously self critical, it is not a bad thing to submit it as such and let the committee decide on outcome for the formal record…

Assorted patch photos to conclude: