Sustainability assessment of Lesser Yellowlegs Tringa flavipes harvested in the Americas

The Lesser Yellowlegs Tringa flavipes has declined markedly over the last several decades, and harvest by humans is emerging as a significant conservation challenge for Lesser Yellowlegs during migration and at wintering sites in the Americas. We used a Prescribed Take Level (PTL) framework to update the previous sustainability assessment conducted by Watts et al. (2015). We first used survey-wide abundance indices for the Lesser Yellowlegs from the Breeding Bird Survey (BBS; 1967–2019) and Christmas Bird Count (CBC; 1967–2021) to fit a Bayesian state-space logistic model, generate posterior estimates of population carrying capacity and maximum population growth rate, and to make abundance index predictions for the current decade. We included annual take (harvest) rates of 0.035–0.235 in the model, which were estimated from the best available information on population sizes and harvest levels. Our model-based predictions for survey-wide abundance estimates for Lesser Yellowlegs on the BBS and CBC will remain below the 2.5^th percentiles of carrying capacity during the current decade, which is considered a minimal conservation objective. We then applied the PTL framework, formulated using three levels of conservation concern to reflect management objectives and two ranges of population size to represent the total and flyway populations of Lesser Yellowlegs. Under all scenarios, our PTL estimates ranging from 5,000 ± 1,945 (SD) individuals to 38,910 ± 13,238 were lower than the 79,450 ± 20,562 individuals estimated by Watts et al. (2015). Considering that a minimum of 18,316–46,940 individuals are harvested annually, Lesser Yellowlegs are likely being overharvested. The analytic framework presented here can be used to assess the sustainability of other shorebird populations to harvesting in the Americas, determine take levels that are compatible with the intent of international agreements and domestic laws, and inform policy and regulatory decision making.