The Flores and Corvo islands are in the Western Group of the Azores archipelago and are around 18km apart from each other. This IBA is the most extensive proposed for the Azores (2,104km2), completely surrounding the perimeter of both islands and including the marine area adjacent to terrestrial IBAs PT053 and PT052. Regarding the bird fauna, this area is very important as a feeding and resting site for the populations of Cory's Shearwater, Roseate Tern and Little Shearwater. The islands within the IBA are the only place in the Azores where Manx Shearwaters breed, with a population of 200 pairs (Monteiro et al. 1999) that are normally found in mixed colonies alongside Cory's Shearwater. Other breeding species include the Common Tern, with a population of over 500 pairs and possibly the Madeiran Storm-petrel. Monteiro et al. (1999) suggests the presence of 20-50 pairs of "hot-season" Madeiran Storm-petrels.
Cory's Shearwater Calonectris diomedea: This species has a population of around 73,000 individuals. Three of the largest colonies in the whole archipelago (around 10,000 individuals per colony) are to be found on Corvo. Most of the fishing and/or resting events for this population during short trips are inside this IBA, and the adults from Faial (June 2006) used it when in transit to the Offshore IBA - PTM014. Manx Shearwater Puffinus puffinus: Flores and Corvo are the only islands that this species uses for breeding in the Azores (Monteiro et al. 1999). Their colonies on these islands are very difficult to access, making monitoring and accurate counting of the effective populations difficult. The use of the marine area by this species requires thorough study. Little Shearwater Puffinus assimilis: The breeding population on Corvo and Flores is estimated at more than 580 pairs. The phenology of this species suggests a regular presence in the IBA, although pelagic areas for the gathering of individuals are also frequent for this species in other locations in Europe (Guilford et al. 2008). Thus, further studies in this IBA should be carried out to better determine its behaviour at sea. Roseate Tern Sterna dougallii: Flores island holds the main population of Roseate Tern in the Azores. The exclusively coastal behaviour of this species (in association with the Common Tern) was very important in the identification of this IBA. On Corvo, this species is observed somewhat less frequently. Common Tern Sterna hirundo: The yearly monitoring survey carried out in this area in 2007 (Neves 2007) estimated the population at a total of 531 pairs that use the marine area in the proposed IBA area. This enables an increase in the importance of this area also for this species that presents coastal feeding habits (Allcorn et al. 2003). Other species observed in this IBA: Great Shearwater, "hot-season" Madeiran Storm-petrel (Monteiro's Storm-petrel), Leach's Storm-petrel, Red Phalarope, Yellow-legged Gull and Pomarine Skua.
BirdLife International (2022) Important Bird Areas factsheet: Corvo e Flores. Downloaded from http://www.birdlife.org on 25/01/2022.