A super nice methods paper out in Toxics: Eeva T, Raivikko N, Espín S, Sanchez-Virosta P, Ruuskanen S, Sorvari J, Rainio M.2021. Bird feces as indicators of metal pollution: pitfalls and solutions. Toxics. We partition between and within individuals and sample types and make recommendations for future analysis for cost-effective but reliable analysesnd among individualstemporal variation and variation