Planning for device failure in bird biologging: evidence-based recommendations from literature and practice

Background Animal-borne biologging has transformed avian ecology by providing fine-scale insights into movement, behaviour, and environmental interactions relevant to conservation, physiology, and wildlife management. Despite rapid advances in biologging technology, device failure remains an inherent feature of field deployments with potential implications for study design, data interpretation, and animal welfare. However, the occurrence and reporting of device failures remain poorly characterized in the literature. We combined a structured literature review and practitioner survey to evaluate the prevalence, reporting, and implications of device failure in contemporary avian biologging research. Results Across 791 studies published between 2021 and 2025 that reported deployments since 2015, 36% reported at least one device failure, although reporting was inconsistent. In contrast, practitioner survey results indicated device failures in 53% of projects, with variable project-level failure rates, including 27% of projects reporting complete failure. The most common causes of failure were transmission issues and battery depletion, though the cause of failure was more often unknown in the literature (61%) compared to practitioner reports (16%). Conclusions Together, these findings suggest that device failure is both common and systematically underreported, limiting the ability of researchers to anticipate realistic device performance, design appropriately powered studies, and evaluate technological reliability. We discuss the ethical, financial, and scientific implications of device failure and propose best-practice recommendations spanning study design, implementation, and reporting. Specifically, we emphasize the importance of incorporating expected failure rates into sample size determination, implementing pre-deployment testing and structured performance monitoring, and closing feedback loops with manufacturers through routine reporting of device performance and failures. Together with transparent, standardized reporting, these practices can support more realistic expectations of device reliability and continuous improvement of biologging technologies. Treating device failure as an expected and reportable component of biologging research will improve the reproducibility, interpretability, and ethical grounding of future avian tracking studies.