I slipped out of gear as soon as the excellent looking field came into view and free-wheeled up blocking the single track road. At first I only noticed three or four Red-necked Stints towards the far end of the field about 100 metres away but these and many others that seemed to appear from nowhere came running directly towards my parked van! I presume it provided some cover in an otherwise very open situation, they flew up nervously several times while I was there but always made a beeline back to the van after re-settling.
As the birds first approached I found what looked suspiciously like a Little. This would be a Japan tick for me so I was more than a little excited and as I watched it another bird, even more distinctive looking, walked into my field of view. Close views of these two along with all the Red-necked provided an excellent opportunity for comparison.
The following three shots show how well the Little can stand out at about 50 metres, this was after one of their short nervous flights. However care needs to be taken as some red-necked have largely solid black mantle, scapulars and coverts and so be just as eye-catchingly dark at distance, though presumably would never show such a bold white mantle V as in the third shot. The other plumage feature that stands out here is the brown breast side, some Red-necked do have browner markings and more warmly marked (more buffish) ground but most are greyish and tend to have neater smaller streaks.
Structurally the views I had of these birds were quite instructive. There's seems to be some contradictory information in the literature regarding proportions, relative leg, tail and primary lengths, but I think this is simply due to differing ways of interpreting the features. Though of course even slight individual variation may lead to confusion with such similar species. In general the Red-necked in these shots certainly look long and attenuated while the dumpier Little looks rather truncated but in fact the Little had both a longer primary projection and extension, but the latter may be an effect of shorter t1. With their more upright stance on longer legs Little look deeper-bellied (and so less attenuated) and these two often seemed to teeter along tipping forward steeply to peck at the mud whereas the shorter-legged Red-necked with flatter undercarriage line gave the appearance of being longer and seemed to glide or hover smoothly just above the surface.
There's unquestionablyly significant individual variation within both Red-necked and Little Stints and images of just two Little aren't going to do anywhere near justice to the full range of possibilities. Nevertheless below are more shots of both Little Stints plus a few Red-necked for comparison.
Long primary projection clearly beyond tail. The tip of p7 is visible beyond the tertials and the p7-8 spacing is large. Note the central tail feather is only slightly longer than the others. The legs are long compared to Red-necked and the exposed tibia between the knee and feathering is much greater and easily seen however much the legs may be bent or immersed in water. Mantle black with fine bright rufous spots and a bold white V. Scapulars black with some grey in the base of central lower row, the innermost visible scapulars are rufous fringed but others have white fringes. Lesser and marginal coverts black. Median coverts, greater coverts and tertials black or very dark grey variably with slightly warmer fringes. Juvenile Red-necked can have largely black-centred scapulars (and coverts) too but these invariably seem to have very prominent white tips with far less conspicuous grey edges and often some rufous in the base. Adult Red-necked scapulars can look very similar to those of these Little Stints but they contrast with grey coverts.
This adult Red-necked Stint has almost identical scapulars but the coverts and tertials are greyer. It also has quite distinct brown breast side streaking. The bill is deeper-based, shorter and blunt-tipped compared to Little. The primary projection is short with p7 coming nowhere near the longest tertial and the spacings between p7-8 and p8-9 are a closer match. The central tail feather is much longer than the others (unlike Little) and the primary projection falls just short of it. The legs are short with relatively little exposed tibia between knee and feathering.
This is the other Little Stint (the first I found) behind a Red-necked. Compared to the Red-necked the bill is longer and finer-tipped. The lesser and marginal coverts are black rather than grey. The legs are long with extensive exposed tibia, best seen on the respective far legs as the Red-necked has a metal ring on the right leg. P7 seems to fall just short of the longest tertial on this bird but it still shows a long spacing to p8.
Further images of the more distinctive of the two Little Stints.
Bill long, over double loral length, dark centre of crown and bold white braces contrasting with largely black mantle and Scapulars. Heavy brown markings on breast sides.
Here compared to Red-necked...
Compared to this adult Red-necked the Little is much longer-legged, the bill is longer and finer at the tip. The primary projection is obviously longer and there are four tips beyond the tertials. This Red-necked has more typically marked lower scapulars plus much greyer coverts.
The brighter juvenile Red-necked in the background is very typical of birds passing through at the moment and though out of focus it accurately portrays the overall colouration of rather warm sandy mantle and upper scapulars and cold pale grey coverts. The differences in primaries and legs is again readily apparent.
Here with a very bright juvenile Red-necked. It's interesting that rufous tertial and greater covert fringes are more often associated with Little rather than red-necked. Though the rufous edges with white tips to the lower scapulars are more expected even if, yet again, the these feathers are far more solidly black than most references suggest. The split supercillium is only more obvious because of the darker crown and more contrasting whiter edgings, the shape is the same to all intents and purposes.
More shots of the other Little Stint...