Friday, 18 January 2019

Blue Concrete Thrushes

The status of Blue Rock Thrush has changed markedly during my time in Japan; when I first arrived it was an almost exclusively coastal breeder as implied by its Japanese name of Iso Hyodori. Inland records were limited to the occasional bird that wintered on tall or prominent buildings, usually meaning in city centres or rural/suburban train stations. I'm unsure when the change began in earnest because they tended, then as they do now, to frequent sites birds wouldn't normally be looked for: not unlike Black Redstarts in the UK. Singing birds in several factory complexes I visited from 2000 were still a novelty but the surprise of finding an inland breeding Rock Thrush quickly changed to one of surprise at finding so many inland breeding Rock Thrushes!

Though quite common inland nowadays, they aren't necessarily obvious and many are probably overlooked. Factories are still a favourite location, one large manufacturing complex I visit in Shiga has two pairs which never seem to leave the confines of the plant. These birds will be quite unknown to the average birder who wouldn't have access to such places, likewise birds way up on roof tops above busy city streets are almost sure to be overlooked unless they are singing. There's a bird that sometimes sings from the roof of my house but its infrequent appearances there, or in the car park to the rear, are no doubt due to a preference for the much taller buildings near by.

Despite their inland spread it remains coastal areas where they are most easily seen. They're common along beaches (with tetrapods), seawalls, canalised river mouths, in other words anywhere with concrete. The more concrete the better it seems. Their affinity to concrete structures is so pronounced as to be off-putting and I rarely bother to stop and photograph them unless I come across an irresistibly posed bird. Consequently I have a lot of random Rock Thrush images disconnected to anything else I might have been looking for at the time which never make it onto the blog. This post starts off with some of the recent ones...

It wasn't really light enough so early in the morning last weekend to take advantage of the opportunity. This bird continued along the roadside until it disappeared behind a truck parked across the street.

Same day, different concrete. A classic bird-on-tetrapod shot. A Dusky Thrush just out of view was naive enough to think it could blithely hop past carrying a corner of rice cracker!

Even sans the reappropriated cracker, the Dusky Thrush wasn't allowed to pass this tetrapod. Time and again, without putting down the cracker, the Rock Thrush would fly at the Dusky until the latter determined there was probably nothing along the beach to the south that couldn't be found with far less effort to the north.

A September male in the same general area. The moth is possibly identifiable but not by me.

Another view of the same bird, the concrete nicely out of focus. Below are two more strongly marked, fresh-plumaged September males.

This is probably my favourite Blue Rock Thrush shot, simply because it's the only one I've taken locally without even a hint of concrete. I was surprised to discover some small island populations (eg on Hahajima, Ogasawara)  are at home in wooded situations completely removed from human structures.  

APRIL on Yonaguni. A worn uniformly blue and red male, compare with the fresh September males above.
And yes, it is on concrete.

MAY on Mishima. A smart looking spring female this time. 

JUNE Wajima. I suppose I don't see as many June birds but I've never seen any other that looks as brown in colouration or has such abraded primaries.

Note to self: look out for Rock Thrushes in June.

Thursday, 27 December 2018

Taiga and Red-breasted Flycatchers wintering in Osaka

I don't think a winter ever passes without at least one Red-breasted Flycatcher in residence in one of the Osaka parks. Big parks, small parks, it doesn't seem to matter. In some years there may be as many as three wintering in different city parks and as I hear reports of birds also wintering in Tokyo parks it begs the question how many are wintering in Japan away from city parks where they're unlikely to be discovered?

This a year a bird chose Oizumi Ryokuchi (the same park as the Grey-backed Thrush last winter), there was simply no way I was going to trek into the southern reaches of Osaka for yet another Red-breasted Fly! When it transformed into a Taiga however, that was a different matter. Both species are scarce autumn migrants in Japan, mainly restricted to the Japan Sea islands; my feeling is that Taiga is the commoner of the two at that time. Both also overwinter in Japan but Red-breasted is definitely more numerous, this Taiga is the first wintering bird I've seen.

Separation of these two scarce flycatchers can be tricky, more so on the islands where observers are less likely to hang around too long waiting for a secretive flycatcher to reappear when there many be many other interesting birds vying for attention. A bird in an Osaka park in winter, on the other hand, doesn't have much competition and good views are guaranteed with a little patience... and photographers' mealworms.

To my eyes most plumage features are open to interpretation, even the diagnostic blacker-than-black uppertail coverts of Taiga. If I see black uppertail coverts which are clearly darker than the tail then all well and good, however, if I don't see blacker coverts can I be sure they are a lighter shade than the tail or is it that I haven't yet seen them well enough, that the angle hasn't been quite right, or that the light is too bright/dim to detect a difference.
Similarly, if the supercilium is obviously brown it must be a Red-breasted, right? I suppose so, and some RBFs do have very warm brown supercilia, others throw in at least a bit of grey and some irds do give a brown-capped impression at times. Is Taiga's supercilium always pure grey throughout? It certainly tends to be that way but I wouldn't stake an ID on head pattern.
The tertial pattern isn't supposed to be diagnostic but I wonder if this might be a one way feature. I've yet to see a Red-breasted with a white edge and terminal spot, 'thorn', on the outer web, they always (the birds I've seen) have a warmer, buffy-brown colouration. Do Taiga sometimes lack a white edge? I don't know, I haven't seen one that lacks this feature but that doesn't mean much considering how few I've seen. Until I learn otherwise this white outer edge and thorn seem a strong indicator to me, and far more easily seen than the uppertail coverts.
So much for plumage.

The bill strikes me as the at-a-glance indicator to species for two reasons. RBF frequently has a paler base to the lower mandible, this is often diffusely very extensive when seen from below. Taiga normally appears completely dark and any pale area there might be will be restricted to a very limited area at the base. The shape of the bill is even more eye-catching. RBF has a comparatively delicate bill in proportion to the head, less deep at the base and with a straighter keel. Thus the curve towards the tip is more prominent on the upper mandible. Taiga has a much deeper-based bill, which isn't in the least delicate, with both mandibles curving towards the tip. It looks more like a bullet stuck on the front of the head.

A typical RBF (Feb 2012). The crown to eyeline is more or less concolourous, the uppertail coverts are most definitely not darker than the tail, the outer webs of the tertials are narrowly edged buffy-brown as is the terminal spot or 'thorn'. The bill has an extensive pale base to the lower mandible and cutting edge of the upper mandible. 

The same individual showing the finer bill.

Another RBF (Jan 2007) with warmer underparts, not all look as obvious as this one. Again, crown to eyeline is uniformly brown and the fine bill is a giveaway.

Taiga (Dec 2018). Those uppertail coverts can't get any blacker than this. The outer webs of the tertials are whitish as are the terminal thorns. Even in this view there is a contrast between the grey supercilium and brown crown. 

The same bird as above. The capped effect produced by the contrast between supercilium and crown is more easily seen here. The white edged tertials are outstanding and the bill enormous.

As above. The bill is far heavier in proportion to the head compared to RBF and those uppertail coverts really are black.

As above. Facing directly into the afternoon sun here and however cold the underparts of Taiga are meant to be there is nevertheless a distinct hint of warmth on the centre breast. There's also a very limited paler area in the base of the lower mandible.

Taiga, Hegurajima (Oct 2015). I'd been watching this bird for a while but as soon as I picked up my camera it was off. Awful as this shot may be I think it's interesting that even partially facing away the bird gives a big-billed impression and also the tertials are white and therefore stand out. Thus I'd say there are features that suggest Taiga when a bird is first glimpsed whereas I'd be more inclined not to have any opinion were it an Red-breasted seen very briefly. 

The holy grail of local photographers is an adult male Red-breasted. It isn't really relevant here as it isn't difficult to identify but it's worth adding a couple of shots because these particular images show to better advantage the difference between uppertail coverts and tail as well as how extensively pale the lower mandible can be.

Adult male RBF (Jan 2016). Setting aside the paler fringes, even the bases of the uppertail coverts are less black than the tail.

As above. With the head tilted slightly away the extent of the pale base of the lower mandible becomes easier to see. In this case you're struggling to find a dark tip rather than a pale base but the point is how extensive the pale area can be without actually appearing obviously so in the field. The following image is of the same bird in profile and the lower mandible looks no paler-based than the previous first winter RBFs above.

As above. The typical finer RBF bill but in profile it's far more difficult to see just how extensive the pale base to the lower mandible is. As I said earlier, wintering birds in parks always give adequate views (because photographers feed them) so identification is never going to be a major issue. Elsewhere, briefly seen birds may have to remain unidentified.

Fortunately there's always the call to put an end to any arguments and all these wintering birds have been quite vocal.

Monday, 17 December 2018

Odd moult timing for Eastern Marsh Harrier?

After birding in Mie the day before, I drove up to northern Lake Biwa and up one of the dead end roads into the forested hill to grab some sleep before dawn. Glum might be a fitting way to describe the morning; the hills were weighed down by low, immobile clouds that early light made very little effort to penetrate. Even the effervescent Bulbuls couldn't muster more than the occasional half hearted, dank-muffled shriek. I persevered in the growning silence, for a while. My mental image of the lake bathed in sunshine, however improbable I knew this to be, proved irresistable.

Once down on the lake the sky overhead was actually blue! I may not have seen the sun but sunlight did reach through the clouds. That was as far as the good news stretched. The backdrop was purples and blacks, sometimes the hills sometimes the sky, there seemed a fluid exchange of hues between the two. This wasn't at all what the forecasters had predicted (Well there's a surprise!) when I was in Mie.

I took advantage of this belated and probably false dawn to welcome back our wintering Steller's Sea Eagle, sitting in its customary spot overlooking the customary line of parked cars and tripods, then check the Taiga Beans on the lake for anything less usual. There wasn't even the usual (that's Gt White-fronts) let alone less usual - I live in hope that the third time a Greylag turns up I will see it. Never mind, the Beans are always spectacular enough without any distractions.

The first drops of rain sent me back to the car before I'd finished scanning for the Red-crested Pochard apparently in residence this winter. If it had been there at the time, it should have stood out like a sore thumb, or giant duck. As it didn't I can console myself that I still wouldn't have seen it had I decided to (be less of a wuss) wait out a potential downpour without protection for my camera and lens.

Two or three minutes further south under a compromise grey pall, no more siren blue interludes, no longer threatening purple and black, I spotted something which really was unexpected; the Harrier of the title. A kerfuffle of Black Kites seemed unsure about what, or even whether, they were mobbing but nevertheless vaguely occupied the same airspace as a juvenile Eastern Marsh Harrier which had no such doubts about chasing off said interloper. This other bird had a distinctly narrow wing tip and was much smaller than the juvenile, this without being sufficiently small to cause serious excitement it must be added. It quickly gained height above the confusion and made off. The juvenile dropped back into the reedbed and the Kites went back to aimlessly wafting around waiting for food to surrender.

Cropped view of the interesting pointy-winged harrier. This is how it actually looked, black against dark grey with a strikingly narrow wing tip. The views were very brief before it was driven off. So, a photographic identification and grit removed from my oyster. 

Heavy cropping (and lightening) reveals p9 is about half grown and p10 is just showing. I don't recall ever seeing an Eastern Marsh, of any age, not having a full set of primaries, hence they must moult remiges at a time of year I don't normally see them (ie summer/autumn).

Due to its small size compared to the juvenile I'm guessing it must be a male. Having discovered p9-10 are still growing it's even easier to to eliminate the miniscule, narrower-winged Montagu's, which has amazingly occurred in Japan in winter. Pallid has also occurred in winter but is just as easy to rule out. Though it might be a better structural match for Hen once fully winged, the underwing pattern visible in the lightened images puts and end to any such notion. Though I don't have experience of older immature female Pied, in gradual transition from juvenile to adult, the lower belly through to the undertail coverts looks too dark I think. It may sound strange to say considering total records but Pied is perhaps the least likely rare harrier to occur in Honshu in winter. And though Northern hasn't even qualified for this paragraph so far, it has to be a better winter bet too.

I confess I'm not one hundred percent sure I've never seen a Marsh Harrier with this moult but I certainly don't remember having seen one. I'd guess this stage of moult would be more likely in an older immature (clearly it isn't juvenile, which wouldn't have started moulting flight feathers yet) because I suspect an adult would have finished replacing its primaries much earlier than December?

In both these images bird's right wing gives us the clearest view of the leading edge of the primaries and it's possible to see alula, very short p10 and half grown p9 creating a stepped effect. Plumage-wise, there's nothing that suggests it isn't an Eastern Marsh Harrier but I wouldn't attempt to sex it if I hadn't seen it in direct comparison with a much bigger (presumed female) juvenile.