The diet of lesser Kestrel Falco naumanni was studied in the Crau the last breeding site of this species in Mediterranean France; an area situated East of the Camargue. Data were collected during the 1992 breeding season and just before the autumn migration in September 1996. The main component of the diet was Insects, predominantly Orthoptera. Among the latter, the high proportion of Decticus albifrons (Tettigoniidae) brought to the nestlings is remarkable. It suggests species selection for preys brought to the young. As Decticus albifrons is exclusively available in non-grazing follows, such a preference has important implications for lesser Kestrel conservation.