Small seabirds are very sensitive to changes in prey availability and thus may be good indicators of changes in prey composition and availability. However, long-term data on diet variation is scarce for tropical tern species. This paper assembles 9 years of data (between 1997-2011) on fish deliveries to Roseate Tern chicks of known age for Aride Island, Seychelles (western Indian Ocean) to examine: a) the role of intrinsic (chick age) and extrinsic (local oceanographic conditions) factors on chick food provisioning and b) the temporal variation in chick intake rate. Our results show a low annual variability in diet composition: 75-97% of all ingested items were goatfishes (Mullidae), which agrees with previous studies showing that this is the main prey fish for the Seychelles seabird community. Chick intake rate (g of fish ingested.chick-1.hr-1) varied considerably among years, from 0.86 in 1997 to 3.12 in 2005, with poor years showing a much higher coefficient of variation than good years. Chick intake rate was significantly correlated with local Chlorophyll-a concentration and sea-surface temperature of the preceding two weeks. This suggests that food provisioning of tropical Roseate Tern chicks is sensitive to fluctuations in local oceanographic conditions affecting the availability of prey fish at a short temporal scale, therefore Roseate Terns are suitable sentinel organisms of local changes in environmental conditions.