Non-invasive methodology for the ecotoxicological sampling of anatids in urban and peri-urban areas

Urban waterbirds serve as crucial bioindicators for evaluating environmental pollution in urban areas, necessitating a focus on tailored non-invasive ecotoxicological biomonitoring methods. This paper adopts a multidisciplinary perspective to underscore the pivotal role of biomonitoring in gauging environmental quality and identifying threats. Emphasizing the versatility and ease of sampling urban birds, we highlight their correlation with human exposure to pollutants, alongside the significant role of wetlands, particularly Ramsar sites, in conservation endeavors and as habitats for migratory birds. Additionally, the paper delves into the relevance of urban birds in monitoring pollutants, showcasing their efficacy in reflecting urbanization or pollution gradients. Proposed non-invasive biomonitoring techniques, including feather and feces analysis, offer practical means to assess heavy metal, microplastics, and other pollutant concentrations without harming the avian species. A comprehensive methodology proposal for waterbird sampling, encompassing pre-sampling activities, basic and specialized laboratory characterization, and data collection in a Central Mexican Ramsar site, is detailed as examples and experiences into these considerations. Concluding insights underscore the impact of emerging pollutants, such as microplastics, on waterbird health and nutritional status, advocating for multivariate statistical analysis to elucidate correlations between morphological characteristics, elemental composition, and pollutant presence.