The elephant estimates derived from an aerial sample count done in Caprivi region, Namibia. The survey was carried out during the early dry season,between May and June 2013 using a fixed wing Cessna 182 aircraft.
Source:Craig, G. C. and Gibson, D. C. (2013a). 'Aerial survey of Elephants and other wildlife in the Caprivi, May/June 2013'. Namibia: WWF.