Wildlife counts in Africa and elsewhere are often implemented using light aircraft with 'rear-seat-observer' (RSO) counting crews. Previous research has indicated that RSOs often fail to detect animals, and that population estimates are therefore biased. We conducted aerial wildlife surveys in Murchison Falls Protected Area, Uganda, in which we replaced RSOs with high-definition 'oblique camera count' (OCC) systems. The survey area comprises forests, woodlands and grasslands. Four counts were conducted in 2015-2016 using a systematic-reconnaissance-flight (SRF) strip-transect design. Camera inclination angles, focal lengths, altitude and frame interval were calibrated to provide imaged strips of known sample size on the left and right sides of the aircraft. Using digital cameras, 24 000 high-definition images were acquired for each count, which were visually interpreted by four airphoto interpreters. We used the standard Jolly II SRF analysis to derive population estimates. Our OCC estimates of the antelopeshartebeest, Uganda kob, waterbuck and oribiwere, respectively, 25%, 103%, 97% and 2100% higher than in the most recent RSO count conducted in 2014. The OCC surveys doubled the 2014 RSO estimate of 58 000 Uganda kob to over 118 000. Population size estimates of elephants and giraffes did not differ significantly. Although all four OCC buffalo estimates were higher than the RSO estimatesin one count by 60%these differences were not significant due to the clumped distribution and high variation in herd sizes, resulting in imprecise estimation by sampling. We conclude that RSO wildlife counts in Murchison have been effective in enumerating elephants and giraffe, but that many smaller species have not been well detected. We emphasize the importance of 60 years of RSO-based surveys across Africa, but suggest that new imaging technologies are embraced to improve accuracy.

Rhino horn is highly valued and this drives the illegal hunting of rhino. As a strategy to counter rhino losses incurred through poaching, managers of African protected areas face pressure to increase the number of rhino in their populations by promoting their growth. These efforts are commonly constrained by being balanced against other protected area objectives which seek to manage toward a “natural ecological state”. This is reflected in the draft continental rhino conservation plan as well as many national‐level rhino plans in Africa, but details on how this can be achieved at a site level are limited; indeed a framework for thinking about the problem is lacking. Here we develop a Theory of Change (ToC) which guides management interventions when seeking to grow rhino numbers at a conservation site. We identify four thematic areas for intervention namely; habitat management; range availability; containment and natural attrition; and rhino population management. As many protected areas are underfunded they seek to attract funding, but many donors are uncertain as to best practice and/or are hesitant to dictate how funds should be spent. This ToC can serve as a framework to guide funding. It can also guide policy in this regard.

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