Holding complete Sarus Crane counts at the beginning, middle and end of the dry season allows us to piece together the complex pattern of crane movements as they move between wetland areas scattered throughout the country.
In January almost all of the cranes were concentrated in the Tonle Sap basin area and Boeung Prek Lapouv, in the Mekong Delta (a total of 601 were counted). Analysis of the 2008 and 2009 shows that large numbers of Sarus Cranes use the Tonle Sap grasslands and nearby seasonal agriculture to forage for food as floodwaters recede. It is possible that a large portion of these birds then move on to Ang Trapeang Thmor (ATT), as figures show an influx of birds in late January/early February. There are similar apparent shifts in numbers between sites in the Mekong Delta. Large numbers of cranes are counted at Boeung Prek Lapouv (BPL) in January, most have disappeared February. At this point, numbers have increased sharply at Kampong Trach-Phu My, peaking in March.
However, there is still a paucity of reliable data concerning seasonal movements, and radio-tracking would appear to be the only method that will ensure accurate data. It is already clear, though, that successful Sarus Crane conservation requires a network of sites spread across their entire range.