Bill length is the most oft-quoted supposed useful field character, but it falls headlong into the oversimplification trap. While bill length may be a useful feature for the eastern-breeding 'mongolus' group (now increasingly recognized as a good species - Mongolian Plover), it is very misleading when used with the western-breeding 'atrifrons' group (Lesser Sand Plover), since the bill of this group is generally as long, proportionately, as that of Greater. In Malaysia, the race we get is 'schaeferi', which is the longest-billed of all the long-billed 'atrifrons' races (there are three), so bill length is not a good indicator at all. Having said that, there is another simplistic feature which seems to work pretty well, especially when there are good quality photos - bill shape. In brief, a Lesser's bill is blunt-ended and bulbous for the final third of its length, while Greater's bill is sharp/tapered-ended and is bulbous for the terminal half of its length. Structurally, Lesser is the more upright and round-bodied of the two, and has a smallish head which often looks rounded and 'cute', and a well-proportioned eye. Greater can look rather long and slender, with a typically more horizontal stance, a large head which often looks angular, and a large eye. Overall, it can give an ungainly impression which Lesser never does. Finally, the legs are appreciably longer (especially the tibia) on Greater than on Lesser, and on juveniles are almost always yellowish (occasionally even orange!). - Eds.