Assessment of the Risk Posed by Interspecific Encounters on Baited Capture Platforms for Monitoring an Endangered Platyrrhine

The conservation of endangered primates often relies on data on population dynamics and health obtained from individuals captured with baited traps. This could increase the risk of injury or predation by attracting competitors and predators to the baited locations. It also can lead to unforeseen interactions of ecological significance among nontarget species. We evaluated these hypotheses by monitoring visits by multiple species to capture platforms for endangered golden lion tamarins (Leontopithecus rosalia). We placed camera traps on ten platforms baited with bananas resulting in more than 1500 species records. We calculated species richness and temporal patterns of visitation overlap among lion tamarins, predators, and competitor species. We also fitted a lion tamarin group with a GPS telemetry transmitter to assess whether movements toward and visits to the platform occurred more than expected by chance. Thirteen mammals and 12 bird species visited the platforms. There was high temporal overlap, albeit with peaks at different times, with the tayra (Eira barbara)—a main predator. Introduced hybrid marmosets (Callithrix spp.) were present on the platforms in 42% of visits by lion tamarins, and we recorded fights between the two species. There was significant temporal overlap between lion tamarins and capuchin monkeys. The lion tamarin visitation rate to platforms did not differ from random locations, nor did they show significant recursive behavior. Lion tamarins were vigilant in 90% of platform visits and emitted mild alarm calls, mobbing calls, and food calls. Their vocal output increased when marmosets were on the platforms. We suggest that lion tamarins consider the platforms an attractive, albeit risky, food resource. Baited platforms attract species beyond the target species and create conditions for unintended potentially negative effects on multiple species.