Distribution and abundance of shorebirds in tidal flats of Sanquianga National Natural Park and the mouth of Iscuandé, Nariño (Colombia), between 2009 and 2020

ABSTRACT 11 % of shorebirds using the American Pacific Flyway are declining and an additional 46 % have no information to estimate their population status. To understand the magnitude of these changes and their causes, baseline information is required especially at sites of concentration like the mouth of Iscuandé River (IS) and the Sanquianga National Natural Park (SNNP). To characterize the composition of shorebird communities there, ten years of standardized counts were analyzed. Using proportional abundance, prevalence and mean density of each location, it was evaluated differences between sites with a different marine influence of the Patía River. IS contributed to 63 % of the average abundance in the study area, where 80 % were small shorebirds. Shorebird abundance in SNNP was 40-60 % among large and small birds, and the contribution of each mouth was proportional to the area sampled. These results show that IS and SNNP host different communities of shorebirds. This spatial heterogeneity has important ecological and conservation implications. The change in their taxonomic and size group composition suggests important differences in intertidal habitat and the organisms who inhabit it and also offers alternatives for the conservation of different assemblages of species.