The Split of Lesser Sand Plover: A Comprehensive Review

*Heri Tarmizi

Image source Google

Recently, the International Ornithological Congress (IOC) has sanctioned the proposed division of Lesser Sand Plover (Charadrius mongolus) into two distinct species: Siberian Sand Plover (C. mongolus) and Tibetan Sand Plover (C. atrifrons). This decision has sparked discussions within the birdwatching community due to the inherent challenges associated with identifying sand plovers. However, this split is not arbitrary; it is supported by robust scientific evidence, particularly from the study conducted by Wei and colleagues in 2022.

Wei et al. (2022) conducted genetic sequencing on individuals from all three proposed species: Siberian Sand Plover, Tibetan Sand Plover, and Greater Sand Plover (C. leschenaultii). Surprisingly, their findings revealed a closer genetic relationship between Siberian Sand Plover and Greater Sand Plover, rather than between Siberian and Tibetan Sand Plovers. This unexpected result prompted a reevaluation of the taxonomic classification within the sand plover complex.

The distribution of the newly recognized taxa is crucial for understanding their ecological niches and conservation needs. The Tibetan Sand Plover breeds in high-altitude, sparsely vegetated habitats ranging from the Tien Shan in Kazakhstan to northeastern India and Tibet. It is further divided into subspecies based on geographic regions. On the other hand, the Siberian Sand Plover breeds in far-eastern Russia, with two subspecies distinguished by their breeding habitats: coastal (C. mongolus stegmanni) and inland (C. mongolus mongolus). Their wintering ranges extend from East Africa to West Indonesia and from South China to Australia, respectively.

The identification of these newly split species poses a challenge, especially considering their morphological similarities. Vocalizations are often used for differentiation, but distinguishing between Siberian and Tibetan Sand Plovers based on recordings alone can be challenging. Therefore, reliance on visual cues becomes imperative.

In terms of plumage, both species exhibit seasonal variations. Siberian Sand Plovers in summer display large white patches on the forehead and muddy flanks, distinguishing them from Tibetan Sand Plovers, which lack extensive white on the forehead and have cleaner transitions between the breast and vent. In winter, Siberian Sand Plovers retain their muddy flanks, while Tibetan Sand Plovers exhibit pure white flanks.

Greater Sand Plovers, now devoid of their "lesser" counterpart, exhibit plumage characteristics similar to Tibetan Sand Plovers, especially in winter. However, their larger bill and pale straw-yellow legs set them apart.

In conclusion, the split of Lesser Sand Plovers into Siberian and Tibetan Sand Plovers is supported by genetic, morphological, and ecological evidence. While identification challenges persist, particularly in the field, understanding the distinct characteristics of each species is essential for accurate observation and conservation efforts.

Image source Google.