We investigated interactions between the Black Redstart (Phoenicurus ochruros) and the St. Lucie cherry (Prunus mahaleb) in two rocky areas in north west Spain. Black Redstarts are responsible for about 30% of P. mahaleb fruit consumption in these areas (604 of a total of 1 854 observations of birds feeding; 56 trees, 4 years). On average 14% of food deliveries to nestlings comprised P. mahaleb fruits (total 8 nests, 3 years; range for individual nests 7-28%). The proportion of deliveries comprising fruits was higher during the second half of the