Sunday, 15 October 2017

Pechora and Red-throated Pipits on Hegura this week

Pechora's silent and skulking nature will mask a few records no doubt but it is a genuine rarity in Japan. And that despite being a fairly common passage bird just across the water in Korea. I've had two or three frustrating October possibles over the years, all on Hegura, all in flight, but only one that gave sufficiently clear views to be sure of. So I was really really pleased to finally nail this one on the ground, or to be more accurate perched up on a stem. In accordance with the Pechora playbook it had flushed silently as I made my stumbling, staggering way through the invisible rocks beneath the tangle of clinging vegetation along the higher section of the beach. Instead of making directly for the horizon as most past possibles had done, it perched long enough for me to clinch the deal. Success at last! This was as good as a tick. Then it dropped back into the thick stuff never to been seen again.

Not so much tram lines as black and white stripes, exposed primaries, black looking coverts with bold white tips, inconspicuous supercilium and contrastingly streaky crown... what more could I want?

...well, mostly pink lower mandible and streaky ear coverts. 

It was worth visiting Hegurajima for the brief views of this fantastic bird alone!

The only bird that might cause confusion is Red-throated and the other side of breakfast I conveniently found the following bird for comparison. One of the features that the literature often mentions in the separation of Red-throated and Pechora is that the latter has dark lores and the former pale lores. This doesn't always seem to be the case, in fact Red-throated often seems to have a very distinct blackish loral line. Red-throated is common enough in Japan for me to see fairly regularly but uncommon enough for me to pay them special attention. I wonder what I would have made of a dark-lored bird had I discovered one in the UK. Of course there are plenty of other features to have pointed me in the right direction but this could have been a source of confusion.

A heavily cropped shot of the Red-throated showing the typical extent of white in t5.

This bird has a clear dark loral line and though this is often most obvious when birds are viewed head-on it's obvious from all angles in this case.

Another darkly marked bird from October a few years ago.

Again from a previous October, this bird has more suitably pale, unmarked lores.

Sunday, 8 October 2017

Swinhoe's Snipe

This bird yesterday is the most recent of the 'dark-winged' snipe (wholly barred underwing and no white trailing edge to the secondaries) I've seen this autumn and as is often the case with the larger snipe it was quite easy to pick up. But which of the likely suspects was it? To be honest though familiar with the distinctive spring Latham's I don't have experience of juveniles. However their southward migration peaks in mid-August (Ohata 1989) and should be over by the end of September (Ura 2007).

This snipe was easy to spot on the broad border of an onion field... and obviously not a Common Snipe.

No mystery about this one though, it's a juvenile Swinhoe's, but it took about four hours before I was convinced of it. Four hours; no wonder Swintail are such a nightmare! There may be no such thing as an easy Swinhoe's or Pintail but there are sometimes enough features to point a reasonably confident finger in one direction or the other. Not so with this bird. After my initial feeling that it could be a Swinhoe's I began to gravitate towards Pintail because of the slightly stumpy rear end, the small, round head and shortish bill, pointing that finger always relies on a combination of suggestive but non-diagnostic features, playing the percentages. There weren't too many out-and-out pro-Swinhoe's features but the very deep barrel chest was one, still, a single feature in favour of one or the other counts for little other than to cast doubt on the alternative possibility. The longer I watched it the more I appreciated how the features I was basing my guesswork on would change from moment to moment. Snipe are masters of the changing head shape and all that entails, eye position, relative bill length, angle of forehead and position of crown peak. The back end is no better with tertial and tail position altering dramatically as a bird feeds, and in this case an unexpected degree of wear was misleading. When eventually a Common Snipe arrived along side it I was jolted back to thinking Swinhoe's because even if the largest Pintail can be a match for any Swinhoe's, those other features that had moved my position towards Pintail had since been fading in and out and no longer counted for much. Suddenly large size was telling me you were right (albeit luckily) in the first place. Finally I managed a view of the outertail feathers and that settled the matter, I could move on to the next field.   

One disconcerting thing was it's very short tail. However, with a good view like this, it's clearly heavily worn with a good length of the tip missing. The tertials are a little worn too but I'm surprised to see such a heavily worn tail. 

This image illustrates very well another concern, or rather combination of concerns, the head looks small and surprisingly rounded thus affecting perception of the eye position. Plus, despite the seemingly small head the bill also looks rather short.

The confirmation that can be so hard to get. Too bad about the weather, it was heavily overcast and raining by this time and my shutter speed was slowing to cope hence this image isn't as sharp as I'd like.

Alongside a Common Snipe its large size becomes apparent but what's even more striking is how much blockier the head looks here and bizarrely the bill seems to have grown! It's because these snipe can change even their structural appearance from one moment to the next that makes judging single images so dangerous.

Below is another presumed Swinhoe's (but no outertails) from a week ago, it shares the same barrel-chested look, in fact it looks very similar in every way except it's a little fresher.

The bill looks a tad longer than the bird today but otherwise the structure is very similar.

White fringes and tips (coverts, tertials) are less worn and brighter. The tail is distinctly longer but the central feathers don't have more than the narrowest of white tips.

Below are images of two other juvenile presumed Swinhoe's together in mid-August. These two are also very similar to each other but intriguingly different to the birds this week.

This was the larger of these two birds in flight, the larger the species the more often individual size difference becomes an issue. Why do I suspect Swinhoe's? Again, it's a combination of suggestive but non-diagnostic points and both exhibit exactly the same features. The rear lower scapulars have concolourous fringes; rare on Pintail but present on about one third of Swinhoe's (Carey and Leader 2003). The primaries extend obviously beyond the tertials and p10 well beyond p9 this could produce a subtly longer, more pointed wing in flight; Pintail shows only a small projection at best, Latham's none apparently. Interestingly the second bird has exactly the same projection which was shown by neither of the October birds. The very long tail has conspicuous white tips to the central feathers. A really puzzling feature of these birds is that both have dropped some (central) median coverts and scapulars yet the two recent birds, almost two months later, show no sign of moult.

The smaller of the two. Lower rear scapulars have concolourous fringes. The tail is long with broad white tips to the central feathers. The primaries extend well beyond the tertials and are easilt visible from all angles. The legs are distinctly yellowish, another variable but suggestive feature. These points can be better seen in the following images. This bird has dropped slightly more median coverts and scapulars than the previous. 

Adults have been thin on the ground and I only have decent images of one from mid-August. But what is it? This bird is the only one that has a greater number of those inconclusive features on the Pintail side of the balance.

Starting with the tail, this is really short, unworn and presumably not growing as this should be moulted on the wintering grounds. The 'white' tips are actually rusty-buff fading to cream. Could Swinhoe's ever have such a short tail? The worn primaries are probably only visible because of the frazzled tertials and p9 is the longest unlike the two juvenile presumed Swinhoe's on which the primary tips are clearly visible and p10 the longest. Is primary spacing relevant?

The head never took on a blocky appearance and was always acceptable for Pintail. Nor did this bird ever show the barrel-chested appearance Swinhoe's often exhibits. 

As it approached it had a slimmer feel to it and when I first picked it up I was expecting it to be a Common.

The grey-green legs are another inconclusive feature which add to the Pintail side of the balance.

Though Pintail can be pretty hulking by all accounts this bird was always rather petite which isn't an adjective I normally associate with Swinhoe's which should never be as small as the smallest of Pintail. The tail is genuinely short and barely projects.

The worn and very faded coverts give the wings a pale and greyish appearance contrasting with the saddle.

Saturday, 30 September 2017

Aggressive stints

A couple of weeks ago at high tide I noticed a party of Red-necked Stints feeding around a small pond just above the beach. One bird was behaving in a very aggressive manor, running at all the other birds with its tail held vertically, bill downward and wings slightly opened while calling loudly. This in itself wasn't so odd but after a few minutes most of the other stints began to adopt the same behaviour until there was very little feeding taking place at all. This wasn't the first time I've noticed this aggressive behaviour and it seems to be a response to insufficient 'personal space' at or around high tide. What I don't remember having seen before is the same behaviour when space is restricted on a muddy field or other similarly cramped inland area.

The following few shots were taken last weekend just as the tide began to drop and the first few exposed square metres attracted the stints. Nothing else arrived until the water dropped further, the stints always seem more impatient to get on with things!

A juvenile Red-necked getting ready to take on all comers.

This adult scores more highly for technical ability and artistic interpretation.

The posturing never has the slightest effect (why bother?) and is followed by the charge.

Later in the day with the mudflats exposed all was sweetness and light... almost.

They would never have co-existed like this earlier in the day. Just having the space available seems to do the trick as they roved this way and that. No need to get excited, the big bird facing away is a Dunlin.

The Little Stint (right) stuck like glue to that small penalty spot-sized puddle. When a Peregrine flushed everything off, it came back to its private pool. The Red-necked Stints, now amicably moving across the mud, little realise they are about to transgress.  

Any Red-necked that crossed the invisible line would cause the tail-up threat posture.

The Little was kept pretty busy.

I never saw the same posturing from the lone Temminck's Stint, it would only voice a warning.