Thursday, 23 March 2017

Bonaparte's Gull in Tsu

After spending two days looking for an already departed Bonaparte's last week you might think I'd have learnt my lesson. But I couldn't get past the possibility that the Black-headed Gull flock that the Bonaparte's was said to be with could still be in Ise Bay. If so, I felt there was a real chance of it putting in another appearance.

The next opportunity I had to test the theory was Wednesday (March 22) and I arrived at dawn. My first port of call was the Anogawa and the sun was already up by the time I climbed onto the embankment. The weather was hardly ideal, apart from the clear sky there was a strong off-shore wind. Sufficiently buffeting to make observation difficult; that my tripod and scope only fell over once during the day was due to me usually laying it flat every time I stopped.

There was a good number of Black-headed on the river but no matter how often I carefully scanned through the two main congregations I eventually had to concede the Bonaparte's simply wasn't there to be found. Next stop the beach.

The upside to the wind was a total absence of people to disturb the gulls. The cloud to that silver lining was only a handful of loafing gulls were interested in having their plumage sandblasted, most preferring the open water well out to sea. No Bonaparte's, no anything much really.

Last throw of the dice and it was back to the Anogawa (the day past so quickly?!); small mercies, the wind was finally beginning to ease. This was good because constantly watering eyes were inducing a dehydration headache.

There are plenty of small Black-headed Gulls, some strikingly so, and at this time of year the bill can be very dark. I spent quite a bit of time scrutinizing one slightly suspicious-looking Black-headed after another but much as I would have liked to turn one of these trickier birds into the Bonaparte's there was no eureka moment. I was doing nothing more than delaying the admission I'd just spent a third day looking for a ghost.

There comes a time you have to admit defeat and I trudged back downstream, one eye checking a trickle of new arrivals, to the small car park behind the seawall at the river mouth. BUT, with only a couple of hundred metres to go, there was the ghost! Coming in off the sea and flying strongly up river back the way I'd just come, white underwings gleaming in the low sun. It really is here! I tried to get a record shot but it was already past me, dancing between low sun and river glare; I'd have nothing, I knew it for sure. Certainly I'd seen the bird but, but, I had to get photographic evidence of a bird which consensus has it departed a week ago.

It joined about 10 Black-headed on the water, I ran. I haven't run for a bird in years! I may be guilty of an unbecomingly fast walk from time to time... but run? I don't think I've run since the St Agnes Nighthawk back in the 70s. That it was 5pm didn't help, there wasn't much daylight left. The small party of gulls lifted... no no No! But quickly they re-settled within a large flock on my side of the river. I mentally marked the part of the flock and when I got there I walked right on by in the best out-for-a-saunter manner I could manage. With the light now behind me thanks to a kink in the embankment I sat and began to scour the spot. I didn't see a raptor but every bird on the river suddenly got up; ducks, egrets, Oystercatchers and naturally the ever-jumpy Black-headed flock led the way. They may always be nervous and ready to fly up for next to no reason but they do at least settle quickly too. Unfortunately I no longer had any idea where in the flock the Bonaparte's might be and most gulls had landed on the exposed mud of the far side of the river a little downstream... again.

I was no longer lingering over slightly suggestive Black-headeds, they either were it or they were not and so far none were. Truthfully, I'm not sure how long I sat sifting through the flock, every so often moving a little further along the bank to check the next section, perhaps 20 minutes from when the birds flushed. But finally there it was! I needed a couple of quick record shots, and then a quick couple more with raised wings. Then I could relax and enjoy the bird. I stayed until the light was too poor to be able to get better views even if the gulls had come to my side of the river. Now I could go for lunch with a clear conscience.

Bonaparte's catching the late sun.

This low sun was actually quite helpful because it would accentuate the red of the Black-headed bills as birds moved around. They could otherwise seem as black-billed as the Bonaparte's.

No matter how much it stretched it was always going to be the smallest gull on the river, at times it was dwarfed but at others it was a closer-run thing.

Small size alone could make it easy to pick out if surrounded by the larger of the Black-headed Gulls.

With smaller birds the size difference was less significant. I presume this Bonaparte's is a female going by head and bill proportions, so a male lurking in a flock of Black-headed would be less noticeable. 

Of course Bonaparte's is really outstanding in flight, very easy to spot as I well know from experience. Once upon a time I was taking a romantic stroll with my then girlfriend along a beach in south west England when a Bonaparte's flew along the tideline. Talk about bad timing. But as the old saying goes 'girlfriends may come and go but a Bonaparte's sighting is for life'. Thus I was able to keep keep one eye on any gulls flying up the river as I made my way back towards the car at 5pm.

Even dinkier in flight but it's the white underside of the primaries compared to the black of Black-headed that really makes this bird so easy to pick out. 

There's absolutely no mistaking it.

The upperwing is very distinctive too. Because the inner primaries lack the black on the under-surface the inner hand is uniform with a more contrasting trailing edge. Whether that's enough to stop you in your tracks if you weren't already looking for Bonaparte's is a different matter.

As a postscript I can add I stayed overnight in the car park hoping to get better views in the morning, however there were relatively few Black-headed present at dawn. Next I went to the beach where the star sighting was Thayer's Gull. By midday I thought the best chance of re-finding the Bonaparte's would be back on the Anogawa in late afternoon. I'm uncertain whether the key factor in its appearance and my finding it yesterday was time, tide or dumb luck. But I was getting tired and decided to call it a day; Bonaparte's securely on my Japan list.

Saturday, 18 March 2017

A second Thayer's Gull in Mie (or so I thought)... but no Bonaparte's

I was gulling in Mie last week and some birders asked my opinion about a Bonaparte's Gull they had found. It was difficult to judge a single back of the camera image, it looked promising but unfortunately the gull had already flown off. However it was seen again during the week and its identity confirmed so I've just got back from two fruitless days looking for it. I was told it probably left with a large transient flock of Black-headed Gulls. This flock contained a number of blue-banded birds one of which I had seen the previous week.

The closest I came to the Bonaparte's? A blue-banded Black-headed Gull which was probably at least on nodding terms with the American.

Fruitless as far as the Bonaparte's was concerned but I did get great views of anadult Thayer's Gull. It's known as Mi-chan apparently, the 'Mi' being the same kanji as in Mie. I got a very brief flight view as it dropped into the middle of a loafing flock and this head shot is the best I could manage.

I was told by a local guller who looked at this image that this bird is Mi-chan, now into her 10th winter at this site! Another Thayer's that also used to winter regularly no longer does so.

This is where my claim of a second Thayer's gets slightly tricky. I'm no expert on the local gull population in Mie. Could it be the bird I saw later was also Mi-chan despite believing it looked different? Just I was getting better views?

Well now with hindsight, and importantly further views of Mi-chan, I can answer that question and in fact I was mistaken, I did only see one Thayer's rather than the two I originally thought. These following images are of the same bird.

I was warned by my informant that there is a hybrid resembling a Thayer's in the area (as well as the usual thayeri-type Vegas) and that care is needed. Presumably there are a number of mistaken IDs. I'm aware of the pitfalls, which doesn't mean I'm proficient at avoiding them of course. This next gull does look more of a pitfall to me. Perhaps it's 'the hybrid' I was warned of, though I'm uncertain what kind of hybrid it could be. Perhaps it's just a Vega with an extreme wing-tip pattern, I do see a few Vega with thayeri-type outer primaries though usually not such a good match as this, but other than the pattern of the outer six primaries there's nothing about this gull that looks out of the ordinary for Vega.

It looked pretty good for a Thayer's coming in like this but that's as good as it got.

Once on the ground things soon began to fall apart. It's just a little too big and heavy, those legs are a little long and distinctly pale pink, that bill seems a tad too robust and the saddle a shade or two too darker than I'd like.

Perhaps the eye is just a little too pale and the eye ring not purple enough. There's an aggregation of too many not-quite-rights. And isn't the black of the outer primaries in the following two images just a little too black...

Monday, 27 February 2017

American Herring Gulls... or imposters?

I'm too busy at work to get out birding at the moment but the scraps of free time I do have allow me to revisit birds I've planned to post about but haven't. A number of interesting puzzles never make it to the blog because they are overtaken by subsequent birding trips.

On 29 January this year I arrived on the beach in Tsu (Mie) at noon while most gulls were still actively feeding along the tideline and hadn't settled into late afternoon loafing groups dotted along the three-kilometre stretch I usually check. As the afternoon progressed birds began to clump together. If proof were ever needed that the grass is always greener, then the worry that it's always the next flock down the beach that's bound have the more interesting gulls provides it. But frustratingly for the addicted guller there are always new arrivals dropping in on each group plus a toing and froing between groups, so the big find is always just one more short walk along the beach. The beauty of gulling on the Yamatogawa in Osaka is that you can settle comfortably in one spot and let the gulls come to you.

Ultimately the effort was well rewarded and the undoubted highlight was a possible first-winter American Herring Gull. My second possible first-winter of the winter!

American Herring Gull is rare in Japan (how many might go unnoticed is another story) and like other North American taxa, or at least records of them, there is a clear northerly bias to occurrence. Theoretically an adult AHG (I don't have firsthand experience) should catch the eye amongst Vega because of the paler saddle, but I wonder whether this might be less obvious on Kansai's Pacific side because of our generally clear skies and bright sunlight throughout winter. In fact it seems there's been an adult in the area for a while now, though I've yet to connect with it. First-winter types might be more outstanding initially but they could be even trickier to confirm because various features can be shown by three taxa commonly found here.

To identify any potential first-winter AHG these all need to be eliminated; the remarkably variable Slaty-backed, Vega (which can look far more like AHG from my European perspective than do European Herring Gulls argenteus or argentatus), and also some Taimyr Gulls at the brown end of their colour range, these can look very like AHG until they take flight. Then there's the hybrid factor to throw into the mix.

Slaty-backed is an extremely variable taxon at this age, amazingly so in fact, and a few birds do suggest AHG in terms of plumage. However a Slaty-backed's structural differences should be apparent. However any SBG x Vega hybrids could potentially present far more of a challenge. The following hybrid (on this same date) suggested a Vega with a coverts bar when I first saw it, but between bouts of preening (and much to my relief) the head and bill proportions were clearly those of Slaty-backed.

I still haven't seen a certain Vega Gull with such a substantial greater coverts bar but this bird gave me a scare. I may even have passed it over as a Vega had it not been preening and showing off that demanding coverts bar. 

Had I not already seen the coverts bar I could easily have passed this over as a Vega if quickly scanning through the flock, but it had already caught my attention and the head/bill structure and proportions are clearly Slaty-backed rather than Vega. In contrast the long, relatively narrow primary projection isn't something I'd expect to see from any Slaty-backed. In fact, apart from the head proportions and the coverts bar this gull looks a standard Vega.

Coming from the UK, but having left before AHG had been recorded, my understanding of the taxon has been fashioned from reports and identification papers heavily weighted towards east coast birds turning up in Europe, stressing overall brownness, uniformity of underparts and frequently an all dark tail and plain tertials to differentiate them from their European counterparts. This probably isn't the best primer when considering AHG from a Japanese perspective. Firstly, though Vega Gull tends to be slightly greyer than the kind of AHG I'd hope to see, it can be uniformly saturated below, anything from cold grey though pale sandy to brown. The greyish variations are commonest. It can also be heavily barred on the rump/upper- and undertail coverts and can more often have an almost entirely dark tail. But reading-up on smithsonianus, I'm led to believe some west coast birds can be less the uniformly brown gull I'd be expecting in Europe; greyer and less uniform overall, some showing more proximal white in the rectrices and  generally edging towards Vega in appearance. Perhaps nailing a first-winter AHG in Japan could be even more difficult than it might be in Europe.

Possibly the most important single feature to separate Vega from AHG is the presence or absence of a prominent greater coverts bar, it's most certainly the feature that's going to grab attention both in flight and at rest. My greatest fear is that some Vega Gulls could show an equally strong coverts bar, I've yet to see an unequivocal Vega with a very prominent bar but such birds could exist. Below are a couple of images of Vega showing a suggestion of a coverts bar, this by no means the worst offender I've seen but, again, they are images of a same-date bird.

It's normal for Vega to have a small group of brown outermost feathers, this bird also has three coverts where the visible dark spots visibly link up to form a solid internal area however there's still a broad white fringe. There's also a certain amount of peppering towards the bases of the outer feathers creating a slightly muddy appearance.

The right wing is distinctly darker but hardly qualifies as a coverts bar. I have seen birds with a more prominent bar than this and the questions really are how substantial can a Vega bar get and how rare are such birds? 

The first of my possible AHGs, and much the better candidate, was two months earlier back on 18 November. I only saw it briefly late in the day and unfortunately missed it fly off while I was changing battery in the camera!

Even head-on, and despite the overlapping flank feathers, dark greater coverts are clearly visible.

Second generation scapulars are already in place and the pale patches on the breast are probably also evidence of moult. The underparts are uniformly dark brown, the vent and undertail coverts densely barred. The solidly dark outer greater coverts and more heavily marked bases inwards, along with the carpal and lesser/marginal coverts create a strong frame to already dark median coverts panel. To me this as much as anything suggests this really is AHG rather than Vega.

A glimpse of the very dark undertail coverts. A few Vega are equally dark.

A 'good' coverts bar, densely barred rump and uppertail coverts plus almost solidly black tail. Because each individual feature can be matched by Vega (apart from a strong coverts bar, I hope) a perfect storm of features on a single gull may make all but the most extreme AHG unidentifiable in Japan. That said, a Vega showing a full suite of AHG features is likely to be much rarer than the real thing!

A closer view and there's no doubt the vent is solidly dark brown and the rump/uppertail coverts show more brown than white.

It looks a particularly long-winged gull at rest, longer at least than the average Vega, but that's pretty subjective. I haven't mentioned the rather uniform blackish tertials as that's yet another feature Vega can match but there's a very obvious difference between this bird and the first-winter Vega in the background. The Vega in the foreground is a sub-adult hence the full primaries at this date (18 Nov), the adult at the rear is typical at this time, as is the adult Taimyr with its retained outer primaries and new inners not yet visible beyond the tertials.

I've significantly lightened this image to try to show the underwing coverts.

And another lightened shot here.

The other taxon to eliminate is Taimyr Gull. Like most, if not all, large gulls they range from overall grey colouration to overall brown. Below is a bird very much at the browner end of the colour range.

On the ground this Taimyr shows a striking superficial resemblance to AHG, it also has a strong brown frame to dark median coverts but even in this partially obscured view the rear belly is contrastingly pale, unlike AHG.

The vent is whitish and sparsely marked.

Once in flight things become much easier. The whiter vent with large brown spots in the longest undertail coverts forming a horseshoe seems typical of the Taimyr I see here.

The rump and uppertail coverts are also mainly white with a horseshoe of bold arrowheads around the uppertails and lines of arrowheads in the middle; no hint of cross bars. The out rectrices are basically white with sub-terminal black, the reverse of AHG. The inner primary window is very subdued with the wings less spread.

The primary window is fairly dark with a strong contrast between the inner and outer webs.

Of course the lack of obvious window and the lack of venetian blinds in the outer primaries also rules out Slaty-backed Gull. So does the long-winged structure of course. If anything you could say Taimyr has the so-called venetian blind pattern on the inner primaries.

So now coming to the recent bird. It would fit in nicely with many images of AHG in California I've seen online. But making a strong case for a bird like this in Japan might be a lot to ask. In the field (29 Jan) I felt it was a strong contender for AHG but checking the images at home doubts crept in. However now that I'm preparing images for this post I'm swinging back towards AHG and feel this meets the criteria for identification as such. Obviously it would be unusual as a Vega otherwise it wouldn't have caught my attention and suggested AHG in the first place. That said, to be 100% certain about the identification is an entirely different matter.

Even at first glance Slaty-backed can be ruled out structure, that long primary projection is wrong. It isn't a Taimyr as the retained scapulars will attest. So Vega or AHG? 

On the pro-AHG side it has a very prominent dark frame to the median coverts panel with a strong greater coverts bar and very dark, uniform marginal coverts. The upper- and undertail coverts are no more heavily barred than many Vega but wouldn't look out of place on many AHG either.

I doubt many Vega (if any?) will have as clear-cut a coverts bar as this. I certainly hope not anyway, put that on a dark Vega and identifying AHG in Japan just became a lot more difficult. 

Even though most  single features wouldn't be out of place on Vega the combination, on top of the bold coverts bar, definitely make this a gull of interest. 

The undertail coverts and vent are heavily marked but the bars are also widely spaced.

The vent is an even brownish. The tertials could go either way but those of Vega are usually far more notched than these. Likewise the primaries aren't convincing; though AHG is meant to have a longer, blacker primary projection I'd defy them to be any blacker than some Vega I see.

A good view of the forewing, the marginal and many lesser coverts are uniformly dark unlike Vega.

My best flight shot; more AHG than Vega on this view. Nevertheless, all I can say with certainty is that the uniform primary window (no contrast between webs) is quite unlike any Taimyr I've ever seen.

So, how many American Herring Gulls? Two...  one...    or none?