Monday, 20 November 2017

The An Ping swiftlets revisited

Catching up with a close Himalayan Swiftlet Aerodramus brevirostris this weekend (with a decent camera for once) furnished me with a few images I could use to compare with the 'summer' swiftlets that arrived in An Ping (following a tropical storm which crossed Luzon and moved west across the South China Sea) in early July two summers ago. My intuition was always that these could not possibly be Himalayan Swiftlets (by date and size of arrival (up to twenty individuals) at least), and that in all likelihood they would have to be Germain's Swiftlets Aerodramus germani. As I now have decent images of what I presume to be both species (with shots of Germain's Swiftlet taken on Mantanani and the Himalayan Swiftlet a 'passage' individual), I can perhaps move a step closer to understanding precisely what these July birds were. The best place to start with making comparisons might be to look first at what images I have of 'known' Germain's Swiftlets ('known' as Germain's is the only swiftlet present on Mantanani), which the two composites below show.

Although there's nothing especially striking about any of the birds above, what is noticeable is that they are structurally very slim-bodied (almost 'pencil-thin'), with elongated 'rears' (i.e. there is 'plenty of bird' beyond the trailing edge of the wing, with the trailing edge 'bisecting' the body somewhere close to half way down its length). The composites below show 'known' Germain's Swiftlets on the left and 'An Ping swiftlets' on the right. Admittedly, the photos of the latter are not the greatest, but it is still hard to find any structural differences of note between these birds, with the An Ping individuals essentially identical the 'known' Germain's Swiftlets in sharing their slender bodies, narrow wings, and 'generous amount' of bird beyond the trailing edge of the wing.

In 'researching' these swiftlets (little more than staring at a small number of potentially mis-captioned photos online), I did come away with the impression that Himalayan Swiftlet might be a 'dumpier' thing than Germain's Swiftlet, with a broader head, 'waist', and tail, and perhaps also wing. The few 'passage' swiftlets I have seen since the arrival of the 'summer' swiftlets have met this expectation, and have furthermore appeared shorter tailed, with an almost Asian House Martin Delichon dasypus 'dumpiness' about them in many cases. None have necessarily appeared 'longer winged' or 'larger' (sometimes cited as differences between Himalayan and Germain's, though presumably only of any real use in the hand); perhaps useless distinctions anyway in view of their very small sizes and acrobatics! The recent Qi Gu bird, too, had the dumpy/podgy look to it that seems common to the 'passage' swiftlets, and not the elongated look of the 'summer' birds.

As my 'summer' swiftlet photos are poor, I'll compare 'known' Germains with this weekend's 'passage' individual below. On the first photo, it is immediately clear that the right-hand bird does have a bigger head, broader neck, more distended belly, and more abruptly tapering rear than the uniformly slim left-hand bird. On the second photo, the differences are less obvious but are still there, with the right-hand bird appearing more 'chunky', almost 'mis-shapen', in comparison to the sleek-looking bird on the left. The left-hand birds are, of course, 'known' Germain's Swiftlets, and the right-hand birds the 'passage' Himalayan. As the 'summer' swiftlets of two years ago share all their structural characteristics with 'known' Germain's and none with Himalayan Swiftlet, the comparison of these two would seem to lend weight to the assertion that they cannot be the latter!

In terms of plumage, there really are no significant differences between these two birds, and it is unclear whether or not the apparent darker head of the Himalayan Swiftlet is just a consequence of the light. It also appears as though the oft-cited paler rump of Germain's Swiftlet is actually of no use as a distinction, either, as the Mantanani Germain's have a darker rump than the Himalayan in one case and a whiter rump than it in another! The only plumage difference I found referenced in the (scant) literature apparent in these photos that may offer hope of the existence of such a thing relates to the undertail coverts. These are said to be dark-centred with a neat white fringe in Germain's and more diffusely dark-centred with a more indistinct pale fringe in Himalayan. Obviously, a sample size of three is not sufficient to consider this difference definitive, but this will certainly be something worth looking at on passage birds as and when they come through. In short, although there's nothing in the plumage that I can point to in these birds that allows me to separate one from the other, there is sufficient present structurally to state with greater certainty that the An Ping swiftlets were not Himalayan, and that the best 'fit' for what they actually were remains Germain's Swiftlet. Above photos taken at various locations in Tainan City and on Mantanani, various dates 2015-17.

Sunday, 19 November 2017

Himalayan Swiftlet

What will probably amount to a 'wall of shame' post photographically, this one, from what has to be said was a very enjoyable and productive week spent birding my local patch. The star of the week remained the Rufous-faced Warbler Abroscopus albogularis, which was still present on site on Tuesday. However, it chose to depart overnight, taking with it the Pallas's Leaf Phylloscopus proregulus and Yellow-browed Warblers Phylloscopus inornatus with which it had arrived.

As threatened, I spent one or two mornings with the cisticolas to make amends for so massively neglecting Bright-headed Cisticola Cisticola exilis during my time here. It's astonishing I've paid such little attention to them, as typically anything cryptic and stripy/streaky is very much my cup of tea! Below first is/are perhaps two individuals (the first photo being one bird and the next three a second) taken on different days. There's no real difference between them, really, and, as the first bird was singing on Friday morning (hence male), they are likely both males. There really can't be that many passerines (of this type certainly) that undergo the kind of structural changes between breeding and non-breeding plumages (from short-tailed to long-tailed respectively) as does Bright-headed Cisticola; in both plumages, this remains a highly attractive species. Just for good measure, I've also added one or two shots of Zitting Cisticolas Cisticola juncidis below. In addition to the white-tipped tail, these also have extensively white pre-ocular supercilia and lack the grey tones to the cheeks and crown of Bright-headed Cisticola. They also seem to lack its scolding call.

The passerines gave way to one or two raptors towards the end of the week, in uncharacteristically still and hot conditions. First to arrive was a juvenile Eastern Buzzard Buteo japonicus on Thursday, flushed out of my coastal woodlot and leaving me only able to helplessly wave it goodbye as it headed quickly inland. At least four Ospreys Pandion haliaetus are also around this winter, and one juvenile did a brief fly-past whilst I was in Area B the same day.

Friday continued with the raptor theme, with a shifty Crested Goshawk Accipiter trivirgatus (a remarkably rare visitor to Qi Gu, despite breeding less than two kilometres away) managing to give me the slip in Area B. A juvenile Eastern Marsh Harrier Circus spilonotus was flapping around in the early morning fog and two Crested Honey Buzzards Pernis ptilorhynchus were just about visible through the low cloud when they came through at noon. Of course, with everything Friday being miles away and not really playing ball, the last thing you would not expect to buck that trend would be a Northern House Martin Delichon urbicum. It didn't, and despite now seeing at least one of these annually, I still remain short of a decent photo of one!

Usually, when Northern House Martins come through, Himalayan Swiftlets Aerodramus brevirostris are not too far behind. I picked up one of these in the incredibly still conditions of Saturday morning (incredible given that a 'strong wind advisory' was in effect). The sighting turned out to be a very fortuitous one, as the minute the wind started to pick up (at about 08:00), the bird cleared out immediately (along with the fifty or so other hirundines with which it had been feeding).

The wind grew in strength very quickly Saturday morning and I was expecting there to be little in my woodlots. A Mugimaki Flycatcher Ficedula mugimaki was therefore a very nice surprise, as was the Red-breasted Flycatcher Ficedula parva which proved a lot more awkward to photograph. Other odds and ends flitting around Saturday included Oriental Turtle Doves Streptopelia orientalis, eight or so of which were frequenting my coastal woodlot, providing further evidence of migration.

The weather changed completely overnight Saturday, as a band of cold air moved south across the island. Rather than bringing newcomers, this simply cleared out everything ahead of it, and my woodlots were once more empty Sunday morning. The only creature in there was one of the resident Chinese Cobras Naja atra, which sloped quietly off before I could get much of a photo of it.

I set myself the absurd goal Sunday afternoon of trying to get Eurasian Coot Fulica atra onto my Qi Gu list. These are 'in' in decent numbers to the south of the river but, as I have never 'made note' of one within the boundaries of my local patch (though most certainly have encountered them on it before), it seemed prudent to try and find another this winter as vegetated pools are now at a premium there (with most having either been drained and filled in or converted into commercial fish ponds (so much for 'national park')). I succeeded in this not too difficult task by finding one out towards San Gu, and this brought the weekend to a comical but nevertheless triumphant end!

So all in all a very typical (and enjoyable) November week in Qi Gu, with both of its speciality diurnal migrants (Northern House Martin and Himalayan Swiftlet) seen, some nice late-moving raptors, and plenty of interesting resident/wintering stuff to play with. The coot moves me very close now to 350 species for Qi Gu, a target I should hit at some point over the winter as there are still one or two other presumed 'overlooked' (or simply forgotten about) species that ought not to be too difficult to find just off the coast. Above photos taken in Qi Gu, Tainan County 14-19/11/17.

Sunday, 12 November 2017

Rufous-faced Warbler

One of those 'miscellany' posts as the find of note this weekend was more of a peculiar one rather than a rare one. I'll start with the male Yellow-throated Bunting Emberiza elegans which spent at least three days this week in Area B, although it took me until Wednesday to photograph it. Eurasian Siskins Spinus spinus and Bramblings Fringilla montifringilla have also been arriving in low numbers this week, indicating that we are in a 'finch year' (after a two-year absence in the case of Eurasian Siskin). These are all flying over, though, and I've yet to train a camera on one.

Friday morning brought the first weird event of the weekend, with the bizarre spectacle of a Streaked Shearwater Calonectris leucomelas flapping around a fish pond close to my coastal woodlot. I picked this up off my scooter (when overhead), but by the time I caught up with it to photograph it, it was at range in private fish ponds where it ultimately manged to give me the slip.

With both woodlots empty Friday, I went looking for waders. The pools around the one which hosted the Spoon-billed Sandpiper Calidris pygmaea two weeks ago are now stiff with waders, offering some hope that this mega might show up again. I could not locate it Friday, but was not unhappy for some reason to spend my time snapping away at Pacific Golden Plovers Pluvialis fulva. If I've aged these two correctly, then there's a winter adult and a juvenile below. The adult is moulting its primaries (which juveniles of this species do not do), so its age is certain. The juvenile has neat grey barring on its flanks and is not in moult. It is perhaps 'mildly' interesting as it has a bit of dark cap, a contrastingly bright (though short) supercilium, and lots of white fringes above (characteristics of American Golden Plover Pluvialis dominica). However, the tertials-tail tip-wing tip ratio is totally out for anything more unusual, and individuals like this one are not difficult to find.

Saturday morning started with a pretty obvious migration of finches, buntings, and warblers along the coast, though everything was moving in very low numbers. My coastal woodlot held the most unexpected find of the weekend: a Rufous-faced Warbler Abroscopus albogularis! This may have simply descended in altitude from breeding areas nearby, though with visible migration in evidence Saturday I suspect that it probably did arrive overnight from the mainland.

Both Pallas's Leaf Phylloscopus proregulus and Yellow-browed Warblers Phylloscopus inornatus were also present in my woodlot, though these were far trickier to photograph. Surprisingly, a Cisticola SP. I photographed on my way out to my woodlot Saturday morning proved to be of greater interest to me than did these, as it exposed just how much I have neglected Bright-headed Cisticola Cisticola exilis over the years! I only ever look at these when they start singing in April, and quite embarrassingly had no idea (until I began reading about them) that non-breeding birds have a completely different tail shape (long and tapered) to breeding-plumaged ones (short and square)! This on its own is sufficient to explain why I have never seen one in winter (I even had the 'scolding' call of Bright-headed Cisticola down as common to both species as birds giving it did not have short tails) though admittedly I spend virtually no time in winter in areas they frequent. To cut a long story short, I revisited the area Sunday with a view to photographing both cisticolas (which I did), but had the settings on my camera wrong meaning that the resulting images would be poor. Basically, Bright-headed Cistiocla can be easily told from the similar Zitting Cisticola Cisticola juncidis by its long dark tail with a buffy tip (as well as by its call). I will want better photos of both of these at some point soon to make amends for this very embarrassing oversight!

With the same birds in my woodlot Sunday as on the previous day, I chose to head up for the recently returned Nordmann's Greenshanks Tringa guttifer at Jiang Jun in the afternoon. I've never fared well with these two, but astonishingly one would come quite close on Sunday, allowing me to finally get decent shots of this fantastically rare species, albeit at the umpteenth attempt!

So all in all a top weekend, really, with returning megas, a first for Qi Gu, and an embarrassingly large amount of 'learning' going on, even at this late stage! Above photos taken in Qi Gu and Jiang Jun, Tainan County 8-12/11/17.