The aerial survey includes the Eastern Floodplain area from the Zambian border to the Nkasa Rupara National Park border. This represents 1042 square kilometer area stretching over a 380-km portion of the Zambesi , Chobe and Linyanti Rivers. The area is surveyed during north-east wetland counts by fixed- ing aerial surveys and hel icopter surveys. Hel icopter surveys use two observers, one data recorder and a pilot. Transects 400m apart are flown at 90km/h, with back doors open for optimal visibility. The helicopter is circled especially for groups of buffalo, lechwe and hippo, to obtain a better count. Some bigger groups are photographed for verification of group size. Fixed-wing aeroplane surveys use standard aerial survey methodology. Al l counts fol low the same flight path and give a 100% sampling coverage of the area. Census numbers available from: 2004, 2007, 2009, 2016.