On 26 August 2011, during a routine survey around the Shabla Tuzla Lake (Black Sea coast of north-east Bulgaria), I observed a small plover of similar size (or slightly bigger and taller) comparing to the Ringed Plover. I immediately noticed that the bird had brownish upper parts, black forehead, and in particular a distinctively rufous-buffish breast band, similar to that of the Greater Sand Plover, which is larger and taller, having longer and more robust bill. I know the latter species very well from Azerbaijan where Branta-Tours regularly operate Birdwatching trips.Separating Greater (Charadrius leschenaultii) and Lesser Sand Plovers (C. mongolus) is far from simple, especially since the various subspecies of the two show some overlap in morphology and biometrics (as well as geographical distribution). However, the bill looked quite short and blunt tipped and, according to the British Birds Vol 73 (1980) Pages 206 - 213, "in Europe, a vagrant sand plover in full or nearly full summer plumage after mid August is likely to be a Lesser Sand Plover, as Lesser moult later than Greater Sand Plover". The black legs were another pro-Lesser Sand Plover feature.
In the light of all the above features it was already clear that I had observed an adult Lesser Sand Plover in full breeding plumage.
During a return visit on 29 August 2011, this time with a British birdwatcher (John Larkin), the Lesser Sand Plover was again successfully observed, photographed and identified, at the same location as three days earlier. The bird was feeding in shallow water and on the mud flats situated on the eastern shore of the lake and was surrounded by several Broad-billed Sandpipers, Kentish, Ringed and Little Ringed Plovers, Dunlins and Little Stints, which provided some valuable comparisons. Observations were made in excellent morning light conditions, at very close range, and using Swarovski Optik equipment.