In the last decade, drones have become an affordable technology offering highly mobile aerial platforms that can carry a range of sensory equipment into hitherto uncharted areas. Drones have thus become a widely applicable tool for surveying animal populations and habitats to assist conservation efforts or to study the behavioural ecology of species by monitoring individual and group behaviour. Here, we review current applications for drone surveys and the potential of recently developed computer algorithms for automatic species detection and individual tracking in drone footage. We further review which factors are reportedly associated with animal disturbance during drone presentations and how drones may be used to study anti‐predator behaviour. Drone surveys of species and their environments allow scientists to create digital terrain models of habitats, estimate species abundance, monitor individual behaviour and study the composition, spatial organization and movement of groups. As drones can influence the behaviour of many bird and mammal species directly, they also provide an experimental tool to study animal responses to novel situations, including the drone itself. We conclude that the combined use of drones and automated detection software can assist population estimates and opens new possibilities to study individual and collective behaviour. With regard to drone‐related disturbance and their potential use as predator models, we recommend to interpret results against the background of population‐specific predation pressure and sources of anthropogenic disturbance.

Research on the vocal behaviour of non-human primates is often motivated by a desire to understand the origins of semantic communication, which led to a partial separation of this research from ecological-evolutionary approaches. To bridge this gap, we returned to the textbook example of semantic communication in animals, the vervet monkey, Chlorocebus pygerythrus, alarm call system, and investigated whether male alarm barks fulfil a dual function of alarming and indicating male quality. Barks are loud calls, produced by adult males, in response to large carnivores. However, since barks occasionally occur in agonistic interactions, we investigated whether barks may also indicate male quality. We recorded natural barking events over 23 months, sampling individual male participation from 45 individuals in six free-ranging groups at the Mawana Game Reserve, KwaZulu-Natal, South Africa. We hypothesized that barking frequency is under intra-sexual selection and predicted that barking frequency would increase with male rank and the degree of male-male competition. We found that the highest-ranking males were more likely to produce barks than lower-ranking males and that the number of daily barking events increased during the mating season. We advocate studying primate communication in its evolutionary context to achieve a comprehensive understanding of call 'meaning'.

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