Wetlands are ecosystems that have been affected by various human processes which have transformed them and their communities. In the present study, we determined the diversity and spatial-temporal variation of the avian fauna of the Humedal Santa Rosa (Lima, Perú), a highly impacted but rich in species wetland of the South American coastal desert. Monthly censuses were carried out between March 2018 and February 2019 using point counts; Simpson and Shannon-Wiener indices were calculated in each station, as well as the monthly turnover between stations (Harrison and Morisita indices); we used extrapolation techniques to calculate the total area richness. October and November showed higher species richness with 69 and 68 species, respectively. The shrub zone, characterized by human intervention, presented the highest values on average for the ShannonWiener index (2.46). October, November, and December showed less similarity and higher turnover between stations coinciding with the beginning of the migrations. Eighty-nine species are reported: Leucophaeus pipixcan with the highest abundance for migratory species and Gallinula galeata for resident species; extrapolation pointed to 90 species (84-95) for this wetland, three of them categorized in the Near Threatened (NT) status, two listed in the CITES Appendix I, and five in Appendix II. Our results suggest the conservation of this ecosystem and its different habitats despite human impacts and its maintenance as an essential shelter for bird diversity on the South American Pacific coast.