The IOC has recently accepted the proposed split of Lesser Sand Plover (Charadrius mongolus) into Siberian Sand Plover (C. mongolus) and Tibetan Sand Plover (C. atrifrons). Sand Plovers have always been notoriously hard to identify, and another species added to the mix is bound to cause some headaches. This proposed split, however, is not without reason: Wei and colleagues (2022) have found that the Siberian population of Lesser Sand Plover is actually closer related to Greater Sand Plover (C. leschenaultii) than it is to the Tibetan population. This finding came as a surprise, considering the morphological similarities between the two populations, which both seemed to have more in common with one another than with Greater Sand Plover. 

Distribution of new taxa 

Tibetan Sand Plover (C. atrifrons) breeds in high altitude, sparsely vegetated habitat beyond the tree line in one continuous population ranging from the Tien Shan in Kazakhstan and Northern China, down through the Pamirs, Karakoram range and Himalayas to NE India, and back up into Tibet and southern Mongolia. This population is commonly split into C. atrifrons pamirensis (west of range), C. atrifrons atrifrons (centre of range) and C. atrifrons schaeferi (eastern side of range). Tibetan Sand Plover winters in coastal areas from E Africa to W Indonesia 

Siberian Sand Plover (C. mongolus) also breeds beyond the tree line in disjointed populations in far-eastern Russia, an accepted split would mean a new Russian endemic breeding species. The new species is split into two subspecies, a coastal C. mongolus stegmanni which breeds in Kamchatka and the Chukotka peninsula while C. mongolus mongolus breeds at numerous inland locations in Siberia. Siberian Sand Plover winters from S China to Australia.  

Map drawn by me, using BirdLife International Data Zone maps and range descriptions from HBW. Take ranges of overlap between C. atrifrons populations with a huge grain of salt; broad, ambiguous HBW subspecies range descriptions were interpreted on a map. I’m sure the plovers have a better idea of what constitutes the line between south and eastern Tibet better than me! 

Wei et al. (2022) findings and discussion 

In 2010, Bradley C. Livezey sequenced the entirety of the Charadriiformes: a diverse order of birds containing gulls, auks and waders. His results suggested that Greater Sand Plover (C. leschenaultii) and Siberian Sand Plover (C. mongolus) were sister taxa.  

A closer look at the Sand Plover complex was necessary, and Wei and colleagues (2022) have removed any doubt that Siberian Sand Plover (C. mongolus) and Tibetan Sand Plover (C. atrifrons) can be considered the same species. Genetic sequencing of at least 10 individuals from each of the three species supported Livezey’s findings that C. leschenaultii and C. mongolus were in fact closer related to each other than either were to C. atrifrons. This shows that the Lesser Sand Plover was in fact paraphyletic with respect to the Greater Sand Plover. Given a lack of hybridisation in overlapping breeding ranges between Greater and Lesser (Tibetan) Sand Plover, it is clear that Lesser Sand Plover must be split. 

While paraphyletic species or ‘paraspecies’ are a natural product of peripatric speciation, and don’t necessarily mean a complex must be split, in this situation, the two ‘Lesser’ Sand Plover proposed species have sufficiently distinct morphological differences.

The study recognises that only members of the eastern race of Greater Sand Plover, C. leschenaultii leschenaultii were sequenced, but this shortcoming should(?) not affect the clear distinction found between C. mongolus and C. atrifrons.  

Hence, only two possible conclusions can be made from the findings. Either the Lesser Sand Plover is split into Siberian and Tibetan Sand Plover, or Siberian Sand Plover is lumped with Greater Sand Plover. However, given clear morphological, vocal and genetic divergence between Greater and Siberian Sand Plover, the former has been proposed to, and accepted by the IOC.  

Some sources I have used have refered to C. mongolus as Mongolian Sand Plover instead of Siberian Sand Plover, such as Nils Van Duivendijk’s ‘Advanced Bird ID Guide’. I would suggest that this given common name would be far too confusing. Siberian Sand Plover (C. mongolus) is only known to breed in eastern Russia (Siberia), while Tibetan Sand Plover (C. atrifrons) and Greater Sand Plover (C. leschenaultii) do actually breed in Mongolia. Hence, naming a species after a country that it doesn’t breed in but it’s biggest confusion species does breed in would be far too confusing. It therefore seems obvious to stop calling C. mongolus ‘Mongolian Sand Plover’.

The proposal also suggests that Greater Sand Plover now be renamed Desert Sand Plover given that there is now no Lesser Sand Plover. I have no strong opinion on this matter; perhaps sticking with Greater Sand Plover would be less confusing?

IDENTIFICATION

All 3 species treated have both a summer and a winter plumage. The wintering ranges of Siberian and Tibetan Sand Plovers are mostly separate, although there is probably an area of overlap in Thailand, Malaysia and Indonesia where all 3 species will occur.

Vocalisations are often the easiest ways to differentiate species, however, reviewing xeno-canto, I couldn’t make sense of the differences between the recordings of Siberian and Tibetan Sand Plovers. I’m sure there are differences, and if anyone has any wisdom on this matter, please drop a comment!

Sadly I couldn’t get permission to use images from the Macaulay library, so I have linked them instead. The first link under each heading shows a typical specimen, I have also linked filtered galleries through which you can test yourself using the criteria listed under each species account. In the future I would love to use images directly in the blog, but sadly, being a student, I can’t afford licensing. I could email individual creators asking for permission, but I’d rather spend time writing and researching.

SIBERIAN SUMMER PLUMAGE

Here’s a link to a typical summer plumage bird on the Macaulay Library.

Here are filtered galleries of photos from Russia and Alaska.

The Siberian Sand Plover shares the same overall proportions of the Tibetan Sand Plover: short tibia creating a short-legged appearance and a short, stubby bill.

The key features to look out for are:

Large white patches on the forehead. While there is some variation, both subspecies have large conspicuous white patches. In the inland Siberian population these seem to be larger, although I have found images of birds from Kamchatka with practically entirely white foreheads.

‘Muddy’ flanks – without a doubt, the most obvious and most indicative feature of a Siberian Sand Plover. In the image linked above, note how the orange breast slowly merges with brown mottles. There is no clear line or distinction between the brown, orange or white. The flanks are a messy mix of all three colours, with brown splodges extending down to the vent.

Another frequently used identification feature is a black line between the white throat and orange breast. In most images I’ve reviewed, the black line is conspicuous in Siberian Sand Plovers, although some Tibetan Sand Plovers appear to show the same line. This feature can be used in conjunction with other features but is not enough for positive ID.

Siberian Sand Plovers are also said to have longer wings than Tibetan Sand Plovers, although I could not consistently identify this feature after reviewing images on the Macaulay library.

The bill of Siberian Sand Plover is also noticeably more stubby than Tibetan Sand Plover.

TIBETAN SUMMER PLUMAGE

Link to a typical pamirensis summer plumage bird from Tajikistan.

Gallery of photos taken in Kazakhstan, Tajikistan and Kyrgystan.

(The bulk of the breeding population is in China, however, the majority of ‘Lesser’ Sand Plover photos on the Macaulay library seem to be migrating or wintering birds, including lots of Siberians. The gallery will be linked later in the article, I recommend testing yourself.)

Immediately, the lack of white on the forehead is obvious. Although many do have white spots, it is never as extensive as in Siberian Sand Plover. Note how ‘clean’ the transition from the orange breast to the white vent is. There are no brown splodges on the vent, and for the most part the transition is gradual and neat. Compare this to the messy, muddy transition from orange to white seen in Siberian Sand Plover. There is also no black line between the white throat and orange breast.

Note that the bill is noticeably less heavy and long than Greater Sand Plover (see below), but longer and more pointed than the stubby bill seen in Siberian Sand Plover.

GREATER SAND PLOVER SUMMER PLUMAGE

Chosen photo of a Summer plumage Greater Sand Plover.

This bird is within the eastern leschenaultii race. It can be told from western races by a lack of orange in the scapulars and mantle. It also has a considerably smaller breast band than the western races.

Gallery of (mostly) summer plumage birds.

The larger size of the bill of Greater Sand Plover is conspicuous and distinctive. The plumage is closer to Siberian Sand Plover: brown splodges are present in the orange breast band but don’t extend anywhere near as far down the flank as in Siberian Sand Plover. The orange on the breast is also far less extensive than in the other two species, almost appearing like a collar.

In the Anatolian (columbinus) race of Greater Sand Plover, the orange can extend down into the flanks, although it never has as much brown splodging. Anatolian plovers will also likely have conspicuous orange marks on the scapulars and mantle.

Although this bird doesn’t have the typical long-legged appearance, the legs are conspicuously straw yellow. Both Siberian and Tibetan Sand Plovers typically have darker legs, as seen in the images above.

SIBERIAN WINTER PLUMAGE

Selected Siberian winter plumage.

A gallery of wintering ‘Lesser’ Sand Plovers in Australia, made up (entirely?) of Siberian Sand Plovers. Note how adults have conspicuous muddy flanks, while juveniles can be very cryptic.

Siberian Sand Plovers retain their ‘muddy’ flanks during the winter, this is particularly evident in flight, but normally obvious when the bird is standing as well. Often the grey-brown on the breast is so extensive that it almost forms a complete ring around the breast. Also note the stubby bill.

Some images of juveniles that I reviewed (told from adults by white fringes to the scapulars) lacked the muddy streaking on the flanks. Separation of juveniles is hence very difficult, the only consistent feature I could find was the bill proportions.

TIBETAN WINTER PLUMAGE

Selected Tibetan winter plumage.

A gallery of (mostly) winter plumage Tibetan Sand Plover in Oman. BEWARE some images appear to be mis-identified Greater Sand Plover which I couldn’t flag as mis-identified as I don’t have enough checklists on ebird.

Both Tibetan and Greater Sand Plover have extremely similar winter plumages. They are readily separable from Siberian Sand Plover by pure white flanks, as seen above. While the bill of Tibetan Sand Plover is longer and less stubby than that of Siberian Sand Plover, it is clearly smaller than the ‘oversized’ bill seen in Greater Sand Plover and looks quite well-proportioned to my eyes.

This individual has yellow legs, which is often associated with Greater Sand Plover. However, it is more of a dark, greenish yellow, as opposed to the straw colour seen in Greater Sand Plover.

When next to each other, the larger size of Greater Sand Plover is obvious, although identification without a reference point is difficult. The only reliable features are bill length, leg colour and vocalisations, however, some birds are sadly better left unidentified.

GREATER SAND PLOVER WINTER PLUMAGE

Selected Greater Sand Plover winter plumage.

The gallery for all Greater Sand Plover images (most are winter plumage birds).

The plumage of Greater Sand Plover is practically inseparable from Tibetan Sand Plover. Note the pale flanks which distinguish it from a Siberian Sand Plover. Note the conspicuously large bill and pale, long, straw yellow legs.

Anatolian (columbinus) are annoyingly known to have shorter bills than their eastern counterparts, this can make separation of wintering Greater and Tibetan Sand Plovers frustratingly difficult in the middle east.

CONCLUSION

The Lesser Sand Plover complex seems, based on current understanding and research, a sensible split. Identification between the two newly split species is mostly straightforward, although some juveniles can be cryptic. Reviewing the Lesser Sand Plover Macaulay library gallery, more birds are readily separated than not (EDIT: now officially split on ebird so this link won’t work as it was intended anymore).