Breeding Madeiran Storm-petrels Oceanodroma castro on Farilhão Grande islet was first described in the early 80s. Despite being an important breeding colony at nationally and global level for the species distribution, few studies regarding monitoring and/or research have been developed. In order to update the knowledge about this population, SPEA, under the FAME project, made 7 visits to the islet between 2011 and 2012. We used mist-nets, nocturnal vocalizations and ground search to assess the population size. The population was estimated to be 473 individuals, resulting in 102-201 breeding pairs, which may indicate a high population decreasing. Comparison with previous studies emphasizes the need to conduct a directed census in order to obtain more robust estimate of this population. For the first time it was used a tracking device (GLS) in Madeiran Storm-petrels to assess movements and distribution of the species during the breeding season. The only GLS recovered showed that the individual made a 5 days trip over open sea to the west coast of Morocco. The walls built in 2002, during an action performed previously by SPEA, which host some Madeiran Storm-petrel nests, were rebuilt. We also implemented 36 new artificial nests that will enable future work with this population. A census of Yellow-legged Gull Larus michahellis that breeds on the islet took place, and 170-180 pairs were estimated. During the several visits to the island, it was detected gulls like signs of predation on Madeiran Storm-petrel. This effect however will be better reported later
