New publication : vultures as sentinels!

Curk, T. Santangeli, A., [...] Melzheimer, J. 2025 Using animal tracking for early detection of mass poisoning events. Journal of Applied Ecology. DOI: 10.1111/1365-2664.70128

 In a shell: Tracking just a small portion of the vulture population can significantly reduce poisoning-related deaths. This study shows that GPS-tracked vultures can serve as effective sentinels, enabling quicker poisoning detection and response, offering a cost-effective and practical strategy to inform conservation efforts.

 Abstract: 

 1. Amidst the sixth mass extinction, some animal groups, such as vultures, the only obligate scavengers among vertebrates, are disappearing at an unprecedented rate. Vulture populations worldwide are declining, primarily due to poisoning. As many vulture species are social foragers, they can congregate in large numbers to scavenge at a carcass, potentially increasing their exposure to poisoning risk. Current anti-poisoning prevention and mitigation measures are insufficient to tackle this threat. There is an urgent need for new effective strategies to prevent mass vulture mortality. 

2. In this study, we applied agent-based modelling using white-backed vulture (Gyps africanus) data from Namibia to: (1) quantify the impact of different foraging strat-egies on vulture poisoning risk and (2) evaluate the cost-effectiveness of using vultures as sentinels for poisoning detection. This approach involves GPS tracking of various numbers of vultures and using the data to quickly detect poisoning in-
cidents and decontaminate carcasses. These actions help mitigate further vulture mortality and prevent mass poisoning. 

 3. Our findings demonstrate that social foraging significantly increases the risk of poisoning among white-backed vultures. However, GPS tracking of individual vultures enables earlier detection of poisoning events, thereby reducing associated mortalities. Poisoning mitigation effectiveness improves with both the number of tracked individuals and the speed of decontamination response. According to
our agent-based model tailored to our study system and species, tracking approximately 5% of the population (25 individuals) offers a good balance between cost and effectiveness, requiring an estimated budget of USD 60,000. Using this strategy and approach, and assuming a response time within 2 h, up to 45% of poisoning-related deaths could be prevented.

4. Synthesis and applications: Our results suggest that, in order to reduce mortality incidences from poisoning in our study system and species, it is sufficient to track a small proportion of the vulture population, which would act as sentinels for the rest. By evaluating the costs and ecological benefits of alternative strategies, varying in number of birds tagged or response time, we provide evidence-based solutions that practitioners can use to design conservation plans. These findings are therefore instrumental in supporting vulture and scavenger conservation policy and practice.