Roque I, LourenÃ§o R, Marques A, Coelho J, Coelho C, Pereira E, et al. Barn owl feathers as biomonitors of mercury: sources of variation in sampling procedures. Ecotoxicology. 2016;25:469-80 pubmed publisher
..The five innermost primaries have lowest mean deviations to both between-feather and intra-individual mean Hg concentration and thus should be selected under restrictive sampling scenarios. ..