Waders

Whimbrel Numenius phaeopus

Whimbrel comprises six subspecies. Nominate phaeopus breeds across northern Europe and western Russia with islandicus breeding in Iceland, the Faeroes and Scotland. These western subspecies are replaced by rogachevae in central Siberia and variegatus in north-east Siberia. A fifth Palearctic subspecies – alboaxillaris (‘Steppe Whimbrel’) – breeds in Kazakhstan and southern Siberia but is very rare. The Nearctic subspecies hudsonicus (‘Hudsonian Whimbrel’) was formerly recognised as a distinct species by e.g. BOURC but is now treated as a subspecies.

Nominate phaeopus and islandicus are common in Britain and hudsonicus is a ‘BB rarity’ here. No other subspecies is on the British List though both rogachevae and variegatus are presumably potential vagrants.

The subspecies hudsonicus is relatively straightforward to identify, showing a wholly brown lower back and rump and brown axillaries and underwing coverts. The subspecies variegatus shows a strong brownish wash or brownish markings in the rump, almost resembling hudsonicus, coupled with strong grey barring on the lower flanks, vent, axillaries and underwing coverts. The subspecies rogachevae has more strongly-barred axillaries than nominate phaeopus but is less marked on the lower back and rump than variegatus. Biometrics are potentially useful for variegatus but not for rogachevae.

Claims of hudsonicus should be acceptable on good field notes. Birds showing characters of rogachevae or variegatus might be acceptable based on detailed notes and good photographs, at least to a rogachevae/variegatus subspecies pair, but biometrics or details from a ringed or marked bird would provide more solid evidence and would certainly be required for allocation to a particular subspecies. (updated Dec 2017 AMS).

References

Chandler, R. 2009. Shorebirds of the Northern Hemisphere. Helm, London.

Hayman, P., Marchant, J. & Prater, A. 1986. Shorebirds: An identification guide to the waders of the world. Croom Helm, Beckenham, Kent.

Prater, A. J., Marchant, J. H. & Vuorinen, J. 1977. Guide to the identification and ageing of Holarctic waders. BTO, Tring.

Tomkovich, P. S. 2008. A new subspecies of the Whimbrel (Numenius phaeopus) from central Russia. Zoologichesky Zhurnal 87: 1092-1099.

 

Curlew Numenius arquata

Three subspecies of Curlew are recognised. Nominate arquata breeds across Europe and western Russia where it intergrades with orientalis (‘Eastern Curlew’), the subspecies occurring east of the Urals. The subspecies suschkini breeds in Kazakhstan and southern Siberia.

Nominate arquata is common in Britain but no other subspecies is on the British List. The eastern subspecies are potential vagrants, however, and birds showing some ‘eastern’ characters have occurred in eastern England.

Identification is problematic. ‘Classic’ orientalis shows brown spotting in the rump, lightly streaked underparts and white, unmarked axillaries and underwing coverts. There is a cline in characters, however. Biometrics are potentially helpful, orientalis being both large and long-billed. The subspecies suschkini resembles orientalis in plumage but in size and bill length is closer to nominate arquata.

Claims of orientalis should contain biometrics or details from a ringed or marked bird. Claims of suschkini would have to rely on a ringed or marked bird. (updated Dec 2017 AMS).

References

Chandler, R. 2009. Shorebirds of the Northern Hemisphere. Helm, London.

Cramp, S. et al. 1983. The Birds of the Western Palearctic. Vol. 3. Oxford University Press, Oxford.

Hayman, P., Marchant, J. & Prater, A. 1986. Shorebirds: An identification guide to the waders of the world. Croom Helm, Beckenham, Kent.

Prater, A. J., Marchant, J. H. & Vuorinen, J. 1977. Guide to the identification and ageing of Holarctic waders. BTO, Tring.

 

Bar-tailed Godwit Limosa lapponica

Bar-tailed Godwit comprises four subspecies. Nominate lapponica breeds across northern Europe. In north-west and north central Siberia it is replaced by taymyrensis, in north-east Siberia by menzbieri and in north-east Siberia and Alaska by baueri.

Nominate lapponica is a common migrant and winter visitor in Britain, with taymyrensis probably a scarce migrant. Neither of the other subspecies is on the British List but both are very long-distance migrants and would appear to be potential vagrants.

The subspecies baueri shows a distinctively dark lower back and rump (therefore lacking a white ‘V’) and heavily-barred brownish axillaries and underwing coverts. It also differs in biometrics, being distinctly large. The subspecies menzbieri is intermediate in appearance between baueri and taymyrensis. It shows a brown-barred white rump.

Claims of a far eastern subspecies might be acceptable based on detailed notes and good photographs, at least to a menzbieri/baueri subspecies pair. Identification to a precise subspecies would probably require biometrics or details from a ringed or marked bird. (updated Dec 2017 AMS).

References

Chandler, R. 2009. Shorebirds of the Northern Hemisphere. Helm, London.

Hayman, P., Marchant, J. & Prater, A. 1986. Shorebirds: An identification guide to the waders of the world. Croom Helm, Beckenham, Kent.

Prater, A. J., Marchant, J. H. & Vuorinen, J. 1977. Guide to the identification and ageing of Holarctic waders. BTO, Tring.

Tomkovich, P.S. & Serra, L. 1999. Morphometrics and prediction of breeding origin in some Holarctic waders. Ardea 87: 289-300.

 

Black-tailed Godwit Limosa limosa

Black-tailed Godwit comprises three subspecies. Nominate limosa (‘Continental Black-tailed Godwit’) breeds in central Europe and central western Russia, islandica (‘Icelandic Black-tailed Godwit’) in Iceland and melanuroides (‘Eastern Black-tailed Godwit’) in central Siberia.

Nominate limosa is a scarce breeder and passage migrant in Britain, islandica a scarce breeder and common non-breeding visitor. The subspecies melanuroides is not on the British List though it is a moderately long-distance migrant and would appear to be just about a potential vagrant.

The identification of melanuroides is potentially challenging. It closely resembles islandica but with, in summer plumage, darker and richer, more saturated hues with more extensive breast and belly barring. It is also said to have a darker forewing and narrower wing-bar (Chandler 2009). Biometrics are potentially helpful, melanuroides being distinctly small.

Claims of melanuroides should contain biometrics or details from a ringed or marked bird. (updated Dec 2017 AMS).

References

Chandler, R. 2009. Shorebirds of the Northern Hemisphere. Helm, London.

Hayman, P., Marchant, J. & Prater, A. 1986. Shorebirds: An identification guide to the waders of the world. Croom Helm, Beckenham, Kent.

Prater, A. J., Marchant, J. H. & Vuorinen, J. 1977. Guide to the identification and ageing of Holarctic waders. BTO, Tring.

 

Turnstone Arenaria interpres

There are two subspecies of Turnstone. Nominate interpres breeds in Greenland, the east Canadian Arctic, northern Europe and Asia and western and northern Alaska, with morinella (‘Canadian Turnstone’) in central Arctic Canada.

Nominate interpres is common in Britain but morinella is not on the British List. However, it is a long-distance migrant and appears to be a potential vagrant.

The differences between the subspecies are, however, subtle. Adult summer plumage morinella is, on average, whiter-headed and brighter chestnut above than nominate interpres. Juveniles and non-breeding adults are more rufous in the wing coverts. Biometrics are potentially useful, morinella having on average a shorter wing and a longer bill and tarsus. It therefore has lower wing/bill and wing/tarsus ratios.

Claims of morinella should contain biometrics or details from a ringed or marked bird. (updated Dec 2017 AMS).

References

Chandler, R. 2009. Shorebirds of the Northern Hemisphere. Helm, London.

Hayman, P., Marchant, J. & Prater, A. 1986. Shorebirds: An identification guide to the waders of the world. Croom Helm, Beckenham, Kent.

Prater, A. J., Marchant, J. H. & Vuorinen, J. 1977. Guide to the identification and ageing of Holarctic waders. BTO, Tring.

 

Dunlin Calidris alpina

Ten subspecies are recognised – alpina (northern Scandinavia and northern Russia), schinzii (southern Greenland, Iceland, Britain and the Baltic), arctica (north-east Greenland), centralis (central Siberia), actites (Sakhalin), kistchinski (Kamchatka and the Kurils), sakhalina (north-east Siberia), arcticola (north Alaska), pacifica (western Alaska) and hudsonia (Arctic Canada west of Hudson Bay).

However, DNA analysis has only identified five geographical groupings – ‘European’, ‘Siberian’, ‘Beringian’, ‘Alaskan’ and ‘Canadian’ (Wenink et al. 1993, 1996, Marthinsen et al. 2007). These authors treat alpina as an invalid taxon, formed by the meeting and mingling of ‘Siberian’ (i.e. centralis) and ‘European’ (i.e. schinzii /arctica) lineages.

Key to any discussion of potential vagrant subspecies in Britain is the taxonomic position and distribution of centralis. Though barely mentioned in the historical literature, most authorities (including IOC) now recognise it and its validity is supported by genetic evidence. There is unanimity in the literature that centralis and alpina intergrade across a large part of north-central Siberia. By contrast, there is a ‘clean’ genetic break between centralis and sakhalina (Wennerberg 2001).

The precise limits of the breeding range of centralis (particularly in the west) are debated. The subspecies is stated by Lappo & Tomkovich (1998) and Tomkovich & Serra (1999) to lie between the Khatanga River in the west and the Kolyma River in the east, intergrading with alpina across the Taymyr Peninsula. Other authors include the Yamal Peninsula within the intergrade zone and Wennerberg (2001) identifies ‘Siberian’ genes in breeding birds as far west as Scandinavia. In the east its range is separated from that of sakhalina which breeds only as far west as north-west Chukotka. The ‘Siberian’ genetic grouping identified by Marthinsen et al. (2007) is reported to breed between the Yamal Peninsula and the Lena River (i.e. even more separated from sakhalina).

The subspecies alpina, schinzii and arctica are all common in Britain, the first as a winterer, the second as a migrant and breeder and the third as a migrant only. No other subspecies is on the British List though all are long distance migrants and have the potential to reach Britain. The circumstantial evidence suggests that centralis probably occurs here. ‘Siberian’ genes linked to the alpina/centralis intergrade zone are reported widely in wintering birds in western Europe as far west as Spain (Wennerberg 2001, Lopes & Wennerberg 2006) whilst core range centralis breeds alongside a wide range of Siberian Arctic waders which routinely reach Britain (e.g. Curlew Sandpiper and Little Stint). Ringing recoveries also link western Europe, including Britain, with this region. The most easterly ringing recovery of a Dunlin in Britain comes from the Yamal Peninsula (Wernham et al. 2002) but other European ringing recoveries come from as far east as the Yenisey. All these locations fall within the reported alpina/centralis intergrade zone.

In addition, any of the other subspecies might also occur in Britain, perhaps particularly the High Arctic breeders sakhalina, arcticola, pacifica and hudsonia. All have long migrations and inhabit regions from which other vagrant waders already reach us but, of the four subspecies, sakhalina (from the east) and hudsonia (from the west) appear to be the most likely to occur. However, any of these subspecies would be expected to be rare here. The subspecies hudsonia has already been suspected here (Stoddart 2007) and a bird apparently of an east Asian/Beringian origin has also been documented (Stoddart 2011).

Dunlins are subject to extensive individual and sex-related variation and intergradation is known to occur between at least centralis and alpina. The only opportunity for subspecific identification in the field lies with birds in fresh breeding plumage in April to June. Subsequent wear renders the features unreliable. Though the subspecies actites and kistchinski are dull above and closely resemble schinzii, most of the East Asian and North American subspecies are whiter and less-streaked below than nominate alpina with brighter orange upperparts and a tendency to less marked scapulars. They show more extensive white on the outer vanes of the inner primaries, producing a larger, more Sanderling-like, wing-bar. Moult timing may also be useful. Biometrics are possibly also helpful, the East Asian and North American subspecies being longer-billed than those from Europe.

Given that there is a cline from alpina to centralis it seems inevitable that centralis could only be fully confirmed if accompanied by a ringing recovery or details of a marked bird or if supported by DNA evidence. As for the other subspecies, sakhalina, arcticola and pacifica (and some hudsonia) are, as a group, quite distinct, forming a discrete Beringian/Nearctic assemblage. They are very close to each other in appearance and so the identification of an out of range bird to a particular subspecies is unlikely to be possible in the absence of a ringing recovery, marked bird or DNA evidence (or, in some cases, biometrics). However, using a ‘suite of characters’ approach it might be possible to assign a bird to a subspecies group, either a Beringian group (sakhalina/arcticola/pacifica) or a more broadly-defined Beringian/Nearctic group (sakhalina/arcticola/pacifica/hudsonia). Notes and photographs might be sufficient for such a diagnosis. If not ‘acceptable’, a good candidate might at least qualify for publication as ‘held’. (updated Dec 2017 AMS).

References

Browning, M. R. 1977. Geographical variation in Dunlins, Calidris alpina, of North America. Canadian Field-Naturalist 91: 301-393.

Chandler, R. 2009. Shorebirds of the Northern Hemisphere. Helm, London.

Hayman, P., Marchant, J. & Prater, A. 1986. Shorebirds: An identification guide to the waders of the world. Croom Helm, Beckenham, Kent.

Lappo, E. G. & Tomkovich, P. S. 1998. Breeding distribution of Dunlin Calidris alpina in Russia. International Wader Studies 10: 152-169.

Lopes, R. J. & Wennerberg, L. 2006. Geographical segregation in wintering Dunlin Calidris alpina populations along the East Atlantic Flyway: evidence from mitochondrial DNA analysis. Waterbirds around the world. Eds. G. C. Boere, C. A. Galbraith and D. A. Stroud. The Stationery Office, Edinburgh, UK pp 541-544.

Marthinsen G., Wennerberg, L & Lifjeld, J.T. 2007. Phylogeography and subspecies taxonomy of Dunlins in the Western Palearctic analysed by DNA microsatellites and amplified fragment length polymorphism markers. Biological Journal of the Linnean Society 92: 713-726.

Miller, M.P., S. M. Haig, T. D. Mullins, L. Ruan, B. Casler, A. Dondua, H. R. Gates, J. M. Johnson, S. Kendall, P. S. Tomkovich, D. Tracy, O. P. Valchuk & R. B. Lanctot. 2015. Intercontinental genetic structure and gene flow in Dunlin (Calidris alpina), a potential vector of avian influenza. Evolutionary Applications 8: 149–171.

Prater, A. J., Marchant, J.H. & Vuorinen, J. 1977. Guide to the identification and ageing of Holarctic waders. BTO, Tring.

Tomkovich, P . S. 1998. Breeding schedule and primary moult in Dunlins Calidris alpina of the Far East.

Wader Study Group Bull. 85: 29-34.

Tomkovich, P. S. & Serra, L. 1999. Morphometrics and prediction of breeding origin in some Holarctic waders. Ardea 87: 289-300.

Wenink P. W. & Baker A. J. 1996. Mitochondrial DNA lineages in composite flocks of migratory and wintering dunlins (Calidris alpina). The Auk, 113: 744–756.

Wenink, P. W., Baker, A. J., & Tilanus, M. G. L. 1993. Hypervariable control-region sequences reveal global population structuring in a long-distance migrant shorebird, the Dunlin (Calidris alpina). Proceedings of the National Academy of Sciences of the USA 90: 94-98.

Wenink, P. W., Baker, A. J., Rösner, H. U. & Tilanus, M. G. L. 1996. Global mitochondrial DNA phylogeography of Holarctic breeding Dunlins (Calidris alpina). Evolution 50: 318-330.

Wennerberg, L. 2001. Breeding origin and migration pattern of Dunlin (Calidris alpina) revealed by mitochondrial DNA analysis. Molecular Ecology 10: 1111-1120.

Wernham, C. et al. 2002. The Migration Atlas: Movements of the Birds of Britain and Ireland. T. & A.D. Poyser, London.