Friday, 28 November 2014

Taiga (Middendorff's) Bean & Tundra Bean Geese, Lake Biwa

I visited the north of Lake Biwa last weekend (Nov 23), the first trip up there this winter. Woodland birding at dawn was good with species like Nuthatch, Willow Tit and Elegant Bunting that I don't usually see around Kyoto all quite common and easily seen.

There was no sign of winter passerines flocks yet, there wasn't any sign of winter for that matter. It was very mild shirt-sleave weather on the mountain top. Next it was down to Kohoku-cho to check whether the Steller's Sea Eagle had arrived yet, still a little earlier than its average arrival date but it was here on the 23rd last year. No luck I'm afraid. Nothing lives forever of course and there's always the worry that this could be the year it doesn't come back, it'll be a big miss when that day does come and we lose such a fantastic bird from our list of regular winter visitors.

Drawing a blank on the Eagle I switched my attention from the hill behind the Kohoku Wild-bird Center to the lake shore in front for a quick scan through the ducks and geese. As things turned out the quick scan that I didn't think I needed my hat for stretched into a much longer stint than planned. By the time I left not only wasn't there enough daylight to visit any good areas further south but I as I was to discover when I jumped in the shower that evening I had a semi-sunburn. That's semi as in the south facing side of my head, rather than semi as in a barely noticable tingle.

There weren't any rare geese present, a Swan Goose put in a surprise appearance last winter and there was a Greylag the winter before, nor were there even any of the Greater White-fronts which have become a regular feature in increasing numbers. However the interesting variation within the usual flock of wintering Bean Geese was enough to keep me occupied.

I've already posted a little on the differing size of some of the Beans at the lake and their bill/head shape range Here. Most of the geese at Kohoku-cho are middendorffii Taiga (Middendorff's) Bean but there also seems to be a small number of Tundra Bean Geese, presumably serrirostris, mixing in with them.

The taxonomy of Bean Geese still leaves questions unanswered and a few images of birds of unknown origin aren't going to confirm racial identity but at least the following digiscoped shots show variation occurring here. It's worth stressing I'm focusing on distinctive individuals in the images I'm posting today, there are (presumed) Middendorff's that might be far more difficult to put a name to if seen out of normal range.

"Middendorff's" Bean Goose is a very large and heavily built bird, the bill is deep-based narrowing towards the yellow band with what almost seems a parallel-edged extension. This is the typical appearance I think of as middendorffii at Kohoku but there seems to be a lot of bill variation within the taxon.  

Another typical long-billed bird. This was one of only two birds I noticed with white at the base of the bill. 

Deep-based triangular bills lacking the elongated tip extension like the bird in the centre aren't uncommon and this was one of three such birds at the end of the flock. At some angles they can seem quite droop-tipped with the combination of arched grin line, straight culmen and bulging lower mandible with a distal kink giving a forward pointing tip. These bills are strikingly different to those of the earlier birds though they seem to be otherwise indistinguishable. Such large geese must be Taiga and presumably this is variation within middendorffii. The bird on the left shows far more yellow than the norm and shows middendorffii can have more than the usual narrow band of colour. 

Another of the group of three deep-based, stubby-billed geese. The grin line is prominent and the lower mandible bulging.

To give an indication of just how large these Taiga Bean Geese are this is an old shot (8 Nov 2013) of a Swan Goose at Kohoku with the local Beans. Of course it could be a small female but nevertheless the comparison is useful.

So there's quite a bit of variation without suggesting anything beyond "Middendorff's" Bean Goose. However the following birds would be very difficult to shoehorn into middendorffii. My understanding of Tundra Bean from a European context is that it has a shorter, deep-based bill compared to the nominate Taiga Beans however this may be misleading from the Japan perspective as middendorffii has a very deep-based bill with a prominent grin patch and some bills are also clearly short and thus triangular, so it's possible that serrirostris might not be so obvious if you're relying on stubbier bills as an initial indicator.

Japan's Tundra Bean Geese winter further north than Kansai and I never get to see those populations. Finding the few birds that may be mixed in with my local Taiga is my only hope of seeing any. But what might they be? The OSJ list states serrirostris (Hishikui in Japanese) and curtis (Hime-hishikui in Japanese) occur in Japan. The former is the common wintering taxon and the latter is rare, though as it may or may not be a valid taxon and may or may not be identifiable in the field I'm not sure how its status can be assessed.

The Tundra I see here are significantly smaller and lighter in direct comparison. The juveniles present this day looked dorsally compressed with a flatter back line, more arched in middendorffii, and the belly less heavy or baggy behind the legs (Taiga is more like a Slaty-backed Gull to reverse the usual comparison). Thus these young geese actually look proportionally longer-bodied, which might not be expected of Tundra. The neck is slightly shorter but the difference is only really apparent when fully extended. They don't look any shorter-legged to my eyes.

With hulking Taiga towering over them on all sides this discrete group of small geese really caught the eye.

Taiga is deep-bodied with a high arching back and low rear belly, hence they look less long in the body, compare with the shot below.

These Tundra Bean Geese have a flatter back and straighter keel compared to the local Taigas. 

The sitting Tundra between the two middendorffii almost disappears into the minimal grass (it's not in a depression) whereas the deep-bodied birds sit high.

The necks are somewhat shorter and proportionately thicker though this isn't especially obvious unless you're looking for it but it may contribute to producing the clearly longer, sleeker-looking carriage of this group.

The small size of the birds in this group was obvious but even more eye catching was how brown they looked compared to Taiga. These juveniles are very distinctive with their plain brown breast and flanks and mostly unmarked scapulars, the narrow tips have mostly worn away, while a couple of more advanced individuals have replaced some rear flank feathers with adult type barring as well as a few darker scapulars showing fresh pale tips. The interesting question is where are the obvious  juvenile middendorfii? There were no stand-out brown juvenile Taiga Beans in the flock of about 200 nor do I remember ever having seen any here. This suggests they could moult into first winter before arrival which might be possible with a more southerly (earlier?) breeding population. It's certainly intrguing and it may be a very good way of picking up juvenile serrirostris in flocks of middendorffii in this area early in winter before their moult progresses to first winter.

Juvenile Tundra with uniformly brown neck, breast and flanks. Scapular fringes worn away and upperparts plain brown. This was the only one of this group that has a slightly convex culmen but as I'm yet to see even a hint of a bulge on the middendorffii this seems significant.

The bird in the centre has the deepest bill with most prominent grin patch of this group. The moult is slightly more advanced with a small number of next generation scapulars and rear flank feathers easily visible. 

The juvenile with the slightly convex culmen again.

Throughout the late morning and afternoon groups of 3-5 geese, perhaps family parties, would fly in to join the main flock and at one point the following single adult came in and landed with the group I was watching. I didn't pay it much attention at the time because the camera was attached to the scope but the incidental images (most out of focus) suggest it is also Tundra.

Though it's a little heavier than the juveniles the size and structure are a good match. The bill is short in relation to the head and there's even a slight forehead stop. The head is chunky with a less rounded hind crown and the neck is short compared to middendorffii.

Dropping in next to the juveniles. 

Short bill compared to head length and the deep-based there's a suggestion of a forehead stop unlike the long straight bill/forehead slope of middendorffii 

Out of focus but still good to compare size with the sitting serrirostris juveniles to the right and middendorffii behind and to the left. 

With the middendorffii more alert this bird's small size is more apparent here. 

As it walked in front of the group of juveniles there's little doubt about the size and structure being similar.

Friday, 21 November 2014

Blue and White Flycatcher - presumed intermedia

Blue and White Flycatcher Cyanoptila cyanomelana is a common breeding bird around Kyoto and males singing from prominent tree-top perches are a major element of the local birding scene in spring. They are also a common migrant and can often be seen in city parks.

Looking through my collection of photographs I find there are far more of females, I suppose partly because the vocal and more frequently seen males are so often way up high and also that there's at least a slight identification interest where females are concerned. After all, what possible identification challenge could there be with a male Blue and White? Or so I used to think.

I found an arresting male on Mishima (Yamaguchi) on 1 May 2010, well before Leader and Carey's Forktail (Aug 2012) paper on the Cyanoptila flycatchers, and wondered if this bird might have been cumatilis for which there was very little available information. Nial Moores was very helpful with information and steered me away from cumatilis and suggested the disputed form intermedia might be more likely to explain the appearance of this bird.

With Zappey's Flycatcher split from cyanomelana, taking the name cumatilis with it, the door opened for increased interest in the east Asian population. Though intermedia may not be universally recognised as a valid subspecies it seems to be gaining ground. It's breeding range on the neighbouring Asian mainland might suggest it could be regular on passage in Japan but like a some other taxa it shares a roughly similar breeding range with (Manchurian Reed Warbler, Daurian Starling, White-throated Rock Thrush to name but three), records seem very few. Its hitherto lack of recognition and perhaps resultant lack of interest or even awareness could be responsible for under recording but the Blue and Whites I see always look just that, with the noteable exception of the bird that prompts this post.

The Leader and Carey paper has a series of plates showing skins of cumatilis, cyanomelana and intermedia but while the former stands out as different the quality isn't good enough to show any tangible differences between the other two. However when I'd earlier seen the bird on Mishima, it had looked quite eye-catching compared to the many cyanomelana passing through at the time.

Unfortunately I was never able to get good views of the back and rump because it was on the edge of woodland on the uphill slope from the road cutting across the hillside. After a few minutes it retreated into the trees and I never saw it again. The following images show the view I did get plus a range of angles of cyanomelana, mostly in similarly bright conditions.

Above are two shots of a cyanomelana showing the distinctive black face, throat and upper breast with white through to the tail. The forehead and crown frequently look a much lighter silvery blue compared to the rest of the upperparts, the brightness and extent can depend on lighting and angle but there's usually a bluer border between the black face and silvery crown giving a capped appearance.
Below are two shots of my presumed intermedia which even at a glance looks quite different. The forehead looks silver rather than silvery blue and the crown as a whole is distinctly paler becoming light blue, rather than deep blue on the nape. The face of cyanomelana normally looks matt black but it can have bluish tips to some feathers if the light catches it. This bird on the other hand is more blue than black and the border between face and hind neck is far less distinct, unlike the lores to forehead division which is sharp from all angles.

Two shots of cyanomelana above (top in shade, bottom in direct light) that show the beautiful deep blue upperparts set off with subtle black detail on the inner webs of the tertials and on the inner webs and outer web bases to the greater coverts. The flight feathers and greater primary coverts are broadly fringed blue giving the overall impression of blue wings, concolourous with the mantle. The forehead and crown have a silvery sheen but as is often the case but this can all but disappear depending on the angle.
Below are more shots showing the general deep blue nape to tail uniformity.

The following shots of the Mishima bird show quite different upperparts colour. Compared to cyanomelana the crown is not only much lighter but also more extensively so and is obvious from any angle. The hind neck is blue but not as dark as that of cyanomelana and the upperparts are uniformly turquoise, the back isn't visible in these shots but the uniformity is hinted at by the visible sides of the rump and uppertail coverts. The tertials, greater coverts, flight feathers and greater primary coverts share the cyanomelana pattern but the turquoise fringes are less conspicuous and the wings look blacker and contrast more with the upperparts. The median and lesser coverts are blue and therefore also contrast with the turquoise upperparts. The greyish wash along the flanks isn't a typical feature of cyanomelana but some do show it to a degree.

Tuesday, 18 November 2014

White (East Siberian) Wagtail - Motacilla alba ocularis

Because I don't have a copy of Alstrom and Mild's Wagtails and Pipits I can't but help feeling like I'm trying to re-invent the wheel looking at wagtails here. Not that I'm failing to make progress; far from it, the oval I've come up with has been a definite improvement on the square I had been using but I don't think I'm quite there yet.

Spring ocularis White Wagtail (East Siberian, or Taiwan Wagtail as it's known in Japan) is a reasonably regular migrant on the islands in western Japan and common in the southern islands. Like other taxa in spring it's fairly straight forward to identify, the uniformly pale grey back and rump with black restricted to the longest uppertail coverts along with a black eyestripe is a unique and instantly recognisable combination. The wing coverts are less cleanly white than those of lugens but nevertheless whiter than the other taxa we're likely to see here while the flight feathers are distinctly darker than lugens creating a strong contrast in the wing. The following series of shots illustrate just how distinctive it is.

Mishima 1 May 2009.

Mishima 30 April 2010.

Iriomote 2 April 2013.

So far so good, but the next bird presents a problem. The median coverts are neatly dark centred with broad white tips and the greater coverts are basically dark with narrow white fringes but again with broad white tips. Thus the coverts are largely dark with two conspicuous wing-bars, totally at odds with the earlier birds. Differing wing pattern doesn't seem to be gender related in other White Wagtails so it's unlikely that this being a female and the others male is the solution. Besides I'd expect to have seen more birds like this if that were the explanation. By early May, when I usually see these birds, they seem to have completed their pre-breeding moult so I don't think it can be age related either as in the field any 2CY should look close enough to adult to be of little significance. Plus images of first winter ocularis I've found on the internet have less well marked coverts than this.

A puzzling dark-winged bird on Mishima, May 2008.

The bird in the following image is far more likely to be a female which seems to lend credence to the previous bird being a dark-winged male.

Presumed female ocularis White Wagtail, 3 May 2010.

Though "East Siberian" is regular in spring this doesn't seem to be the case in autumn and the following image is of the only putative first winter I've seen.

I believe this to be a first winter ocularis, due to the grey greater coverts with narrow white fringes. Simply because this bird was on Hegurajima doesn't make it more likely to be a rarer taxon but it is a location where autumn ocularis could turn up. Hegurajima, 7 October 2011.

A more heavily cropped version of the same shot, the only one I got of the bird before it flew off. The sides of the rump are less black than on over 40 first winter type lugens I photographed in Kyoto in October 2014, though I wouldn't rely on that too much given the variability shown in general.

A juvenile/first winter lugens. Mie, 20 September 2014.

White Wagtail M.a.lugens is a very common year-round bird in this area, it's possible to go out and see well over 100 on any given day in October. However despite significant and confusing first winter/non-breeding female variation at that time of year I've never seen a bird with these obvious piano key coverts. In fact though first winter lugens are reporterd to lack the white coverts of adults there isn't a vast amount of age related difference. One of the reasons for the difficulty in aging some female types in the field. Even the most strongly marked juvenile and first winter lugens coverts are less distinctly patterned grey, most have just a slight greyish wash of limited extent and others are almost fully white.

Below are a number of shots showing the normal range of first winter lugens coverts to compare with both the putative first winter ocularis and the earlier dark-winged bird.

Two shots of a (possibly female) first winter lugens with very white coverts, Kyoto 18 October 2014.

First winter lugens with limited greyish centres to greater coverts, Kyoto 18 October 2014.

Closer to juvenile judging by the greyer forehead, this bird has more prominent but still limited grey centres to the coverts. The black upper border to the supercillium may indicate male. Ishikawa, 10 October 2014.

Even with the coverts spread the typical bird has largely white coverts. Kyoto 18 October.

This bird still has a grey forehead and is closer to juvenile than other birds present on this date. The coverts are greyer than most birds too but the markings are smudgy rather than sharply defined. Kyoto 18 October.

Kyoto 18 October. 

Much darker bases to two of the median coverts (which look the same generation) compared to other birds, Kyoto 18 October.

I still live in hope of getting a smoother ride out of my oval wheel one day.