A strategic method for expanding the Pacific Flyway Motus network
Understanding the movement and survival of birds of conservation concern during migration is critical for guiding conservation action. Unfortunately, the migratory life stage is understudied in many bird species because of the challenges of following such species over large distances, particularly those with small body sizes. One established method for tracking movement of small avian species is the Motus Wildlife Tracking System. This international collaborative network provides a powerful tool for tracking survival and movement, enabling estimation of parameters such as stopover duration, migratory connectivity, dispersal, and survival that are otherwise difficult to measure. While the Motus network is well established in eastern North America, coverage in the western part of the continent is limited, constraining sample sizes needed for robust demographic modeling. Expanding the Motus network is therefore a high priority for Pacific Flyway agencies. To date, methods for determining priority locations for new Motus receiving stations do not explicitly incorporate species occurrence. In collaboration with partners across the western United States and the Canadian Province of British Columbia, we used eBird data to prioritize strategic locations for new Motus receiving stations. We modeled multi-species co-occurrence, defined by abundance thresholds met in multiple weeks, using environmental and survey covariates while accounting for imperfect detection. Using occupancy model predictions, we identify high-use areas where new Motus stations are most likely to detect multiple species of interest. While the predictive maps provide a framework for strategically expanding the Motus network and supporting conservation of migratory stopover and wintering habitats in the Pacific Flyway, we also provide the analysis code and prediction output to support the expansion of Motus in additional regions.