Spatiotemporal distribution of birds at the Guerrero Negro Saltworks, BajaCalifornia Sur, Mexico

The saltworks development located near the Ojo de Liebre-Guerrero Negro coa stal lagoon system, in Baja California Sur (Mexico), conforms a modified ha bitat used by resident and migratory birds. To describe the species composi tion, distribution and abundance of this avifauna, 12 monthly censuses were performed in the area, from December 1995 to December 1996. Ninety-five sp ecies were identified. Changes in the number of species during the study pe riod (from a maximum of 61 in January to a minimum of 39 in July) are relat ed to the presence or absence of migratory and/or wintering species. Fiftee n of the species are protected by the Mexican Government under some kind of status (two endangered, seven threatened, one rare and five under special protection). Changes in the abundance were also related to the occurrence o f migratory and wintering birds, with the highest numbers recorded between August and December. The lowest abundance, 5,561 birds, was recorded in Jun e and the highest, 72,951 birds, in August. The most abundant species were Phalaropus lobatus (24.1% of the overall record), Calidris mauri (23.2%), P odiceps nigricollis (13.8%), Limosa fedoa (6.4%) and Branta bernicla (6.2%) . These results confirm that this area is ornithologically important.