Mauritanian Spoonbills (Platalea leucorodia balsaci) only breed at Banc d'Arguin, Mauritania, West Africa. Their populations have declined; however, nothing is known about possible ecological factors involved, including their primary food and foraging habits. Home range sizes, habitat selection, and foraging rhythm in six adult Mauritanian Spoonbills were documented by attaching backpack harnesses with solar-powered satellite GPS-transmitters. Based on 18 bird-months of data (5,844 selected ground positions) collected between 2008 and 2010, these individuals never left the study area centered on the island of Tidra. The fixed kernel home range size was 23–101 km² ( = 62 km²) and the core area 2–14 km² ( = 7 km²). Home range sizes did not differ between breeding and non-breeding seasons. Mauritanian Spoonbills fed only in intertidal areas where they preferred the seagrass-covered (Zostera noltii) areas and they fed primarily during the ebbing tide. Furthermore, the GPS-positions away from the high tide roosts were strongly associated with creeks dissecting the seagrass beds. During the non-breeding season, foraging occurred throughout the 24-hr period, but during the breeding season they foraged exclusively by night.