The snowy plover (Charadrius nivosus) is a shorebird that is threatened in Mexico and US. The breeding population of the Pacific coast is a distinct population segment (DPS) whose distribution goes from Washington, USA, to Baja California Sur, Mexico. San Quintin hosts 50% of the DPS of the Baja California peninsula and, therefore, is a priority site for the species. Historical (1991) and current surveys (2007-2014), plus information on marked and recaptured birds, were used to assess population changes in the DPS nesting in the Baja California peninsula. It was estimated that between 1991 and 2008 the peninsular population declined by 33%. However the population of San Quintin did not follow this trend and it was considered stable. In Winter the resident population of plovers of San Quintin doubled by the immigration of individuals from the north. Density of plovers in the breeding season, although variable, was higher in salt works and sandy beaches. In the last 2 winters there was a shift in the plover distribution between sandy beaches and salt flats. Conservation of the Mexican DPS depends 50% on habitat protection and conservation in San Quintin.