ZoologybioRxiv
Drone-based effective counting and ageing of hippopotamus (Hippopotamus amphibius) in the Okavango Delta in Botswana
V. Inman, R. T. Kingsford, K. E. Leggett, M. J. Chase
This study compares drone and land counts of hippos in the Okavango Delta, finding drones more effective for population estimates but less so for age classification in early mornings.
DOI 10.1371/journal.pone.0219652