Water Pipits at Staines Moor

It is estimated that only 190 Water Pipits spend the winter in the whole of the UK² (a surprisingly small number I think), mostly in south-east England. The first Water Pipit recorded at Staines Moor was a single bird by the River Colne back on 3 April 1954¹, but with a mean maximum of nine birds wintering each year since 2000, and high counts including 13 in 2002, 15 in 2005 and a site record of an incredible 16 present in March 2003¹, Staines Moor has become known locally as a reliable site for these scarce continental visitors. In fact Staines Moor must surely be the premier London site for this species, and rank as one of the very best sites in Britain! I am occasionally asked where best to look on the Moor, so I thought I'd give some pointers on how to find them.

Dogs are an ever present source of disturbance at Staines Moor nowadays, so Water Pipits can often be tricky to find and getting reasonable or prolonged deck views can be frustrating to say the least. They are often seen flying over, when the best way to pick one up is by their flight call (fortunately they are often very vocal). However, they frequently associate with Meadow Pipits, so even if you do hear one you will likely to be confronted with several pipits flying over, not just one. These photos highlight the key flight features in winter plumage to help pick one out.

Winter plumage Water Pipit Anthus spinoletta (left) and Meadow Pipit Anthus pratensis (right) - photographed at Staines Moor in 2013

The most striking feature of Water Pipit in flight is the very white underparts with streaking largely restricted to the breast and just faint streaking on the flanks (top left and center left). This creates a vivid contrast between the underparts and the wings, also the white vent contrasts markedly with the black under-tail. By comparison, Meadow Pipit is a pale buff below with bold streaking on the flanks clearly visible (top right and center right), creating far less contrast.

Viewed side on or from above, the wing bars are bolder on Water Pipit than on Meadow Pipit (top left and top right), and given good views the pale bold supercilium is usually visible (top left and bottom left), and much more obvious than on any well marked Meadow Pipit (top right and bottom right), and the tertials on Water Pipit also have bolder pale edges. Also, Water Pipit appears longer (they are longer tailed and longer winged than Meadow Pipit) and less dumpy then Meadow Pipit, with a slightly longer and finer bill and stronger flight.

Water Pipit, Staines Moor, 22 January 2013

For a comparison of flight calls see below.



Rock Pipit Anthus petrosus is extremely rare at Staines Moor with just two records - one on 20 October 2000 and an individual of the Scandinavian race A. p. littoralis beside the Colne on 15 Mar 2003¹. However, Rock Pipit occur frequently at the adjacent reservoirs and so should not be ruled out. For an excellent video on separating Rock from Water Pipit click here.

Water Pipit occur at Staines Moor from October to May (by which time they have often acquired their beautiful summer plumage). They are most frequently found foraging along the banks of the River Colne, especially between the two footbridges (also check the willows by the southern footbridge). The large vernal pool next to the swamp in the south-east corner of the site is another favoured area (where they sometimes perch up in the hawthorns), as are the channels and pools west of the Colne and the two iris channels in the north-west corner.

Map showing the areas on Staines Moor most frequently visited by Water Pipits. Water Pipits can be found anywhere
on Staines Moor (as well as on adjacent Stanwell Moor). The banks of the Colne are the most reliable place to look,
but they also feed in the channels, around the floods and in the grass, and often perch on the hawthorns (alternate
click and open in a new tab or window to enlarge).

References

¹ Dingain, L. (2013) The Avian History of Staines Moor. Lond. Bird Rep. 76: 214-226.
² Musgrove, A. et al. (2013) Population estimates of birds in Great Britain and the United Kingdom. British Birds 106: 64-100.

Seebohm's Wheatear

Most often considered conspecific with Northern Wheatear Oenanthe oenanthe, the Moroccan and Algerian race, O. o. seebohmi or Seebohm's Wheatear, is actually a very different looking bird. After dipping at one of their best known breeding grounds, Oukaimeden in the High Atlas, at the start of our trip to Morocco last month (they hadn't arrived), we thought we'd blown our chances of seeing them, but a few days later found a migrant male at a wadi near Tinejdad. It seems we were very lucky to find a bird on passage as according to Thévenot (2003) in The Birds of Morocco, "outside breeding range, [there's] only few records of migrants". For me, this was one of the most interesting birds on the trip.

Seebohm's Wheatear Oenanthe oenanthe seebohmi, near Tinejdad, 16 March 2013. The pale grey upperparts and very white
underparts with no orange-buff, creates a distinctive 'cold' look compared to Northern Wheatear. Note the faint peachy-buff wash
to the undertail-coverts and vent - a feature I've not found mentioned in the literature?

I'm a little confused over the age of this bird. Presumably the white edges to the tertials and tips to the primary, greater and medium
coverts age this as a 1st summer male? There are photos on the internet of males with no white edges which are presumably 2cy
birds. The black throat-patch looks very extensive here, reaching the upper breast and almost reaching the carpal.

Fig 1: Notice the weak black 'band' across the nape - a feature noticeable on other photos on the internet but which I've not found
mentioned in the literature. Fig 2: Note the rather narrow black terminal tail-band and white tips to the tail feathers. Fig 3: The black
underwing coverts are diagnostic (cf. Northern Wheatear here).

Seebohm's Wheatear breed in the Rif and Atlas mountains of Morocco and also in northern Algeria, but in contrast to nominate oenanthe are a short distance migrant (so unlikely to make it to Britain, but just imagine one on the patch!), wintering in southwest Mauritania with some only making it as far south as Saharan Morocco.

The notorious tapaculo

In 2007, Mouse-coloured Tapaculo S. speluncae, a species found in the mountains of the Atlantic Forest in South America, was split by the Brazilian Committee of Ornithological Records (CBRO) and renamed Serra do Mar Tapaculo Scytalopus notorius (after the Serra do Mar mountains of the region). Birders everywhere (okay, birders in Brazil) were just starting to get used to the new name when the CBRO suddenly, and mysteriously, reversed their decision!

The Scytalopus genus of tapaculos are arguably the most taxonomically complex passerines in Latin America. Typical tapaculos, they are extremely difficult to see which makes them very tricky to study. In fact, they appear to like nothing more than remaining hidden from frustrated birders by creeping around mouse-like in dense vegetation, while monotonously calling their heads off! But over the last few decades new populations have been discovered and the genus has seen enormous taxonomic changes, with around 40 species now recognised compared to just 11 in 1970³. Associated with mountains, most are found in the Andes but some are restricted to south-east South America where six species are now recognised, three of which have been described since 2005!

The specific name of Mouse-coloured Tapaculo - speluncae - has long been the subject of intense taxonomic debate, with ornithologists divided over whether this is the same species originally described and given this name. The answer not only has significant implications for the nomenclature of Mouse-coloured Tapaculo, but also for other Scytalopus species recently discovered in south-east Brazil.

What's in a name? The nomenclature of Mouse-coloured Tapaculo Scytalopus
speluncae has long been a topic of intense debate, with ornithologists divided over
whether this is the same species described and attributed the specific name
speluncae by Édouard Ménétriés in 1835. This male at Pico da Caledônia, Rio de
Janeiro state, Brazil, in October 2007, was laughing so uncontrollably at our efforts
to work it out, that it momentarily forgot that it was supposed to be skulking around
in dense vegetation annoying birders and allowed itself to be photographed out in
the open for a change.

In 1835, French zoologist, Édouard Ménétriés, collected and described the first Scytalopus tapaculo in the region - an adult male collected in the Espinhaço mountains in Minas Gerias state, near the town of São João del Rei, that he named Malacorhynchus speluncae (placed in the genus Scytalopus today). Ménétriés described it as uniform mouse grey above, slightly paler grey below and becoming whitish towards the middle of the breast and on the throat (illustration of type specimen below). Subsequently, similar, albeit darker birds were discovered in the Atlantic Forest mountains in Rio de Janeiro state, a long way from the Espinhaço mountains, and identified by ornithologists Hellmayr (1907) and Ihering & Ihering (1907) as belonging to the same species (know today as Mouse-coloured Tapaculo).

Surprisingly, no other Scytalopus tapaculos were subsequently found in the São João del Rei region and so ornithologists questioned São João del Rei as the type locality of Ménétriés specimen³ (a notion given credence after the type localities of other specimens collected by Ménétriés were found to be erroneous), suggesting it was actually collected in the Atlantic Forest.

Illustration of the S. speluncae type specimen described by
Ménétriés in 1835. Note the whitish throat, grey flanks with no
buff and pale legs. (Édouard Ménétriés)

Then in the 1990s, not one but two forms of Scytalopus tapaculo were discovered hiding out in the Espinhaço mountains - one in the northern part of the range (described in 2005 as Diamantina Tapaculo S. diamantinensis), and the other in the south around São João del Rei! However, these São João del Rei birds are quite different, morphologically and vocally, to the Atlantic Forest taxon, being paler grey, noticeably whitish on the central belly and most significantly, buff with dark barring on the flanks, rump and under tail coverts (photo here)³. They were clearly a different species, and so which species had Ménétriés described? Was it the São João del Rei species afterall, or a bird from the Atlantic Forest as suggested? Whichever one it is must be attributed the name speluncae, and the other would need to be described as a new species.

Scytalopus tapaculo species discovered at São João del Rei,
the type locality of S. speluncae described by Ménétriés.
Note the obvious buff barred flanks and rump, medium grey
underparts and pale legs. (Vitor Torga Lombardi)

A study by Raposo et al. published in 2006, re-examined Ménétriés's type specimen and compared it with new topotypes collected from São João del Rei, as well as specimens from the Atlantic Forest. Although the specimen is damaged, they found a few buff feathers on the rump and flanks of the type specimen (not mentioned by Ménétriés) and argue that these, together with the whitish central belly and throat and paler mid-grey colouration, are all features not found on the Atlantic Forest birds³ (especially adult males¹). Therefore, Ménétriés's type specimen must be from São João del Rei, and so the name speluncae must be applied to this form and Mouse-coloured Tapaculo must be described as a new species, for which they proposed the name Serra do Mar Tapaculo Scytalopus notorius (notorius because of the controversy surrounding the species).

The following year, this proposal was adopted by the CBRO and the issue seemed to be settled, but then three years later a similar study by Maurício et al.¹ concluded completely the opposite! They point out that the plumage of adult male Mouse-coloured Tapaculo actually varies considerably - ranging from homogeneous blackish grey with no traces of any buff feathers (as put foward by Raposo et al.), to mid-grey with some buff barred feathers on the flanks and rump (a feature shown by about 25% of adult males). In contrast, the São João del Rei taxon exhibits a very clearly marked plumage pattern (see above), being dark grey above and paler grey below a whitish center to the belly and obvious buff barred flanks, vent, under tail coverts and rump. They showed that the buff feathers on Ménétriés type specimen are nowhere near extensive enough for it to be the São João del Rei species, and also the central belly on the type is actually medium grey and not white. However, the plumage of Ménétriés type falls well within the variation found within Mouse-coloured Tapaculo, and therefore the Atlantic Forest species must retain the name speluncae.

In the end, Maurício et al. won the support of the South American Classification Committee and the CBRO reinstated Mouse-coloured Tapaculo as the name of the Atlantic Forest species. With this issue finally laid to rest, the São João del Rei species could be formally described, and in 2010 was announced as a new species - Rock Tapaculo S. petrophilus.⁴

Adult male Mouse-coloured Tapaculo Scytalopus speluncae, Pico da Caledônia,
Rio de Janeiro state, Brazil, October 2007. Same bird looking less smug now that
ornithologists have finally worked out what it is! Endemic to the mountains of the
Atlantic Forest, this is the darkest and most uniform in plumage of it's genus in
south-east Brazil, but they are variable, with the male sometimes showing some
buff on the flanks or rump. Note the dark grey plumage, very slightly paler throat,
lack of white on the underparts and dark legs and bill.

References

¹ Maurício, G.N., Bornschein, M.R., Vasconcelos, M.F., Whitney, J.F., Pacheco, J.F. & Silveira, L.F. (2010) Taxonomy of "Mouse-colored Tapaculos". I. On the application of the name Malacorhynchus speluncae Ménétriés, 1835 (Aves: Passeriformes: Rhinocryptidae). Zootaxa 2518: 32–48.
² Raposo, M.A. & Kirwan, G.M. (2008) The Brazilian species complex Scytalopus speluncae: how many times can a holotype be overlooked? Revista Brasileira de Ornitologia 16(1): 78–81.
³ Raposo, M.A., Stopiglia, R., Loskot, V. & Kirwan, G.M. (2006) The correct use of the name Scytalopus speluncae (Ménétriés, 1835), and the description of a new species of Brazilian tapaculo (Aves: Passeriformes: Rhinocryptidae). Zootaxa 1271: 37–56.
⁴ Whitney, B.M., Marcelo, F.V., Silveira, L.F. & Pacheco, J.F. (2010) Scytalopus petrophilus (Rock Tapaculo): a new species from Minas Gerias, Brazil. Revista Brasileira de Ornitologia 18(2): 73-88.

Focus on Azure-shouldered Tanager

Azure-shouldered Tanager Thraupis cyanoptera is a scarce and often elusive Atlantic Forest endemic that birders sometimes struggle to distinguish from the much more abundant Sayaca Tanager Thraupis sayaca. However, given reasonable views they can be told apart fairly easily.

Azure-shouldered is slightly but noticeably larger and bulkier than Sayaca Tanager, but the size is not always apparent unless the two species are seen side by side. Much more obvious is the general colouration - Azure-shouldered Tanager is turquoise above with brighter turquoise outer edges to the flight feathers, tertials and greater coverts, and a contrasting duller turquoise grey below (this contrast is sharply defined even on the head and neck). Sayaca Tanager is a very variable grey-blue and generally concolorous above and below, with turquoise tones restricted to outer edges of the wing feathers. On Azure-shouldered Tanager the electric blue lesser coverts are diagnostic but not always visible (especially on 1st winter birds), and the blackish lores and black extending very slightly behind the eye forming a very short faint eye-stripe (visible at very close range) are another key feature. Azure-shouldered also shows a slightly heavier bill (that is often blackish on the upper mandible and greyish on the lower mandible, but not always), but both species show very dark (blackish) inner webs to the tertials, upper wing coverts and flight features on the closed wing.

Sayaca Tanager is abundant in forest edge and semi-open habitats and very conspicuous, even in cities, whereas Azure-shouldered Tanager is a scarce forest interior species that tends to stick to the canopy and is therefore much harder to find. Last July I spent some time at Andy and Cristina Foster's superb photo hide at their Serra dos Tucanos lodge in Rio de Janeiro state, and was able to study this Near-threatened species in some detail. These photos illustrate the features nicely.

Azure-shouldered Tanager Thraupis cyanoptera, Serra dos Tucanos, July 2011.
Note the contrast between the turquoise nape and crown and the grey blue face,
ear coverts and underparts. The electric blue lesser coverts are not always
visible.

Azure-shouldered Tanager Thraupis cyanoptera, Serra dos Tucanos, July 2011.
The blackish lores are a key identification feature when distinguishing from Sayaca
Tanager, but are not often mentioned or illustrated in field guides.

Azure-shouldered Tanager Thraupis cyanoptera, Serra dos Tucanos, July 2011.
The blackish lores create a rather aggressive facial expression (cf. Sayaca
Tanager below).

Azure-shouldered Tanager Thraupis cyanoptera, Serra dos Tucanos, July 2011.
The faint dark eye-stripe is easier to see in this shot of the same bird in the shade.
Note the dark upper mandible.

Azure-shouldered Tanager Thraupis cyanoptera, Serra dos Tucanos, July 2011.
Note the turquoise forehead, crown and nape contrasting sharply with the greyer
ear coverts and neck. The black inner webs to the tertials, coverts and primaries
and black primaries contrast vividly with the turquoise outer webs.

Sayaca Tanager Thraupis sayaca, REGUA, RJ state, July 2011. Note the grey blue
plumage, with turquoise tones restricted to the outer edges of the wing feathers.
The lores are concolorous with the rest of the face, isolating the dark eye. The
race found in south-eastern Brazil, T. s. sayaca, has no white in the wing.

The main contact call of Azure-shouldered Tanager is a simple, sharp, high-pitched downslurred seep (reminiscent of Redwing Turdus iliacus), whereas Sayaca Tanager has a shorter and rather almost squeaky call which has upwards deflection in the middle. The sonograms below clearly show the difference.





The songs are quite similar, both being a high-pitched, squeaky notes, but Azure-shouldered is faster, more repetitive and more continuous. Compare below.





The taxonomy of tanagers (Thraupidae), as with many Neotropical bird families, is currently in a state of flux. Azure-shouldered Tanager and Sayaca Tanager are traditionally both placed in the Thraupis genus along with 7 other species. But molecular studies have revealed that the Thraupis is actually paraphyletic (have more than one common ancestor) and consists of 2 clades. Azure-shoudered Tanager, despite having a similar morphology, is actually part of a different clade to Sayaca Tanager, and so will probably be moved to a different or new genus at some point. In the meantime, the Brazilian Committee of Ornithological Records (CBRO), rather confusingly, has moved all species currently in Thraupis into the Tangara genus, effectively removing the Thraupis genus altogether. However, other authorities (including the AOU) have yet to adopt this taxonomy and so I've remained faithful to the traditional classification here.

Brazilian moorhens - a laughing matter

When I first visited Brazil over five years ago, I soon became aware of how different the long 'cackling' calls of the local race of Common Moorhen Gallinula chloropus galeata are compared to the familiar short calls of nominate G. c. chloropus back in the UK. A closer look at these birds also revealed that they look a little different too, being slightly bigger with a larger red shield with a broad square top edge, giving the head profile a peak at the front of the crown. With the recent taxonomic scrutiny of moorhens focusing on the variation between Old World and New World forms, much has been written about the morphological differences between the North American race G. c. cachinnans and Old World chloropus, that might allow a transatlantic vagrant to be identified. Adult cachinnans, in addition to the features above, tend to show a different bill pattern with less extensive yellow on the lower mandible and a more clearly defined red/yellow border, a duller red iris and richer reddish-brown upperparts, particularly on the upper mantle where there is a more clearly demarcated contrast with the dark grey neck (see here and here). Immature birds are much more similar and possibly indistinguishable in the field?

In July, the AOU (but so far not the BOU) decided to split all New World forms from Old World chloropus as Common Gallinule (in favour of the name Laughing Moorhen suggested by The Sound Approach). However, it is galeata, the most widespread form across South America, that has been designated the nominate race rather than cachinnans. I'd like to know what features distinguish these two races? As far as I can tell they are vocally inseparable (compare the calls of galeata and cachinnans here and chloropus here), but I've observed that galeata does appear to be much greyer on the upperparts than both Old World chloropus and North American cachinnans, with brown tones restricted to the lower mantle, rump, greater coverts and flight feathers (compare below), and perhaps they are also a little darker overall. Are there other differences?

Former race G. c. galeata, now split by the AOU as Common Gallinule Gallinula
galeata, REGUA, Brazil, November 2011. Note the large, square-topped shield, the
well defined lower mandible pattern and the dark eye. galeata seem to have much
greyer upperparts than both North American cachinnans and Old World chloropus.

Common Moorhen Gallinula chloropus, London Wetland Centre, UK, December
2011. Note the smaller, narrower shield with a rounded top, slightly more extensive
yellow on the lower mandible with a slightly less demarcated pattern, brighter red
iris and browner upperparts (click to enlarge). North American cachinnans is
apparently even browner above.

At REGUA, galeata also exhibit some differences in behaviour compared to the Old World Common Moorhen. Here the birds seem to be more social, forming large flocks throughout the year, often containing 40 or so individuals that feed and rest together. They also appear to be more aquatic in their feeding habits, preferring to forage in open and often quite deep water, picking plant material from the surface, and feed much less frequently on land than Common Moorhen do in the UK, where bird seem to prefer to graze on grass. Has anyone noticed a similar feeding behaviour in cachinnans, or in any other race? For some excellent footage by Ron Jackson showing the behaviour, calls and features of galeata at REGUA, click here.

A typical feeding group of Common Gallinule Gallinula galeata, REGUA, July
2011. Based on observations at REGUA, Brazilian birds are seemingly much
less terrestrial in their feeding habits than their Old World counterparts?

Common Moorhen Gallinula chloropus London Wetland Centre, UK, December
2011. Birds in the UK seem to prefer grazing on land.

So is the situation as straightforward as separating New World from Old World moorhens? Looking at photos, meridionalis from sub-Saharan Africa and St. Helena in the mid South Atlantic (here), orientalis of south-east Asia (here), and pyrrhorrhoa from Madagascar and surrounding islands (here), all look very similar to galeata to me, with perhaps a very slightly more rounded top to the shield. Have these been allied to Common Moorhen or Common Gallinule, and are they also different species?

Overcoming euphonia phobia

Euphonias are a genus of small short tailed passerines found throughout the Neotropics, which together with the chlorophonias, comprise the subfamily Euphoniinae. Showing a higher degree of sexual dimorphism than their chlorophonia cousins, male euphonias of most species are brightly coloured, distinctively marked and generally fairly easy to identify. The females on the other hand are mainly dull olive-green with various amounts of grey, and their similarity, along with often poor illustrations in field guides, means that unless they call many birders simply don't bother with them. Six species of euphonia occur regularly in the Brazilian Atlantic Forest and at first glance the females of all but one of these, Golden-rumped Euphonia, are fairly similar in appearance. However, given good views and knowing what to look for, separating them is not too difficult.

The most common species in the Atlantic Forest is Violaceous Euphonia. The female (Fig. 1 & 2) is uniform olive-green above and below with dark grey inner webs to the primaries, tertials, medium and greater coverts. This is the only euphonia in this group with no grey on the underparts (note that female Golden-rumped also has olive-green underparts, but is easily distinguished - see here).

Perhaps the most distinctive is female Chestnut-bellied Euphonia (Fig. 3 & 4). The upperparts, flanks, ear coverts, chin and forehead are a rich yellow-green and it is the only species with red undertail coverts and vent. The grey center to the breast and upper belly extends onto the neck sides to form a half collar that is separated from the grey nape by green ear coverts.

Click to enlarge

Female Purple-throated Euphonia (Fig. 5 & 6) is also distinctive, once you get your eye in. The general jizz is of a paler but more contrasty bird, with the colours on the upperparts often looking rather washed out. The upperparts are mainly pale olive-green becoming greyer on the mantle, nape and crown, and contrast sharply with the bright lemon yellow flanks, vent and undertail coverts. The breast and belly are pale grey (sometimes almost white) which set off the dark grey legs. The head pattern is also rather distinctive, with dark grey or black lores (meeting across the top of the bill) and faint narrow black eyestripe behind the eye, contrasting with a bright yellow forehead and hint of a yellow supercilium before the eye. The bill is a little longer and more conical than the other species, with a blackish distal half (more so on the upper mandible), and at close range the split white eye-ring is diagnostic. The blackish upper tail, and inner webs to the tertials and inner primaries add further contrast to the upperparts.

The two most similar of the set are Orange-bellied Euphonia and Green-chinned Euphonia. The females of both are olive-green above, pale grey below with olive-yellow flanks extending onto the undertail coverts. Orange-bellied Euphonia (Fig. 7 & 8) is polymorphic, but the form in the Atlantic Forest has a grey nape that stretches around the neck forming a very diffuse grey collar. In comparison, Green-chinned (Fig. 9 & 10) shows obvious grey neck sides extending onto the ear coverts, an olive-green nape and dark grey lores. Structurally, Green-chinned is a heavier looking bird with a noticeably thick bill, compared to Orange-bellied that has a small and rather delicate looking bill.

Acknowledgments

Many thanks to Leonardo Pimentel for permission to use his photos of Green-chinned Euphonia.

Spring male Northern Wheatears

With reports nationally of an early passage of Greenland Wheatears (Ssp. leucorhoa), I was interested to see if any of the Northern Wheatears passing through Staines Moor over the last couple of weeks could be assigned to this race based on field observations. In his article, Greenland Wheatears (Birdwatch 214: 26-27), Peter Clement points to several features that help separate leucorhoa from the nominate oenanthe in the field: larger size (up to 20%), richer orange-buff underparts extending onto the belly and down the flanks (not restricted to the throat and breast like oenanthe), a broader black tail band, longer wings (by up to 9 mm) and, on males, deeper blue-grey upperparts. However, with variation within our own birds and Icelandic birds showing an intermediate morphology, surely positive identification of birds bound for Greenland would be difficult if not impossible in the field?

At the moor the majority of male birds seen in the last two weeks have showed characteristcs associated with Greenland Wheatear. However, there was a fair bit of variation, and often the structure, posture and colour of a particular bird has appeared to change slightly depending on the light conditions and behaviour.

Click to enlarge

Figs 1 & 2 show fairly classic looking oenanthe birds - a slight, fairly compact structure with the orange-buff largely confined to the throat and upper breast and the rest of the underparts whitish. Note that the bird in fig 2 has a more clearly defined mask and supercilium, appears bulkier due to its posture and is whiter below. In comparison the birds in figs 4 & 5 show a heavier structure, richer orange-buff extending throughout the underparts and perhaps a clearer and bolder black mask and white supercilium. Fig 5 shows the same bird as fig 3 in flight - note the broad black tail band that's over a third, and almost half the length of the tail. Martin Garner suggests an interesting supporting feature for Greenland birds, where their longer wings show between 7-8 primary tips on the closed wing, compared to 6-7 on the nominate race. The bird in fig 6 clearly shows 7 primary tips (click to enlarge), which I guess could place it either camp, but doesn't rule out Greenland. To my eyes, the blue-grey on the upperparts looks pretty much the same on all these birds.

I suspect the identification of actual Greenland Wheatears can only be confirmed with biometrics, but we can at least say a bird 'shows characteristcs of' a bird from Greenland, Iceland or Fenno-Scandinavia, and it was certainly good fun trying to work it out!

More on Greenland Wheatears here:
http://www.birdwatch.co.uk/categories/articleitem.asp?item=692
http://birdingfrontiers.com/2011/04/09/greenland-wheatears/
http://steveblain.blogspot.com/2011/04/leucorhoa.html
http://peteralfreybirdingnotebook.blogspot.com/2011/04/northern-northern-wheatears.html