Peregrine falcon
Ilhéu de Cima is famous for its seabird colonies. Ilhéu Grande, which has been used by goat farmers and whalers in the past, does not currently support breeding seabirds, though large colonies must have existed formerly as the island has thick layers of guano. The island group has been identified as an Important Bird Area (IBA) by BirdLife International because it supports seabird colonies as well as peregrine falcons and Iago sparrows. Birds include the Frigate bird ("Pelagodroma marina") numbering around 1,000 in 1989, the Boyd's shearwater ("Puffinus boydi"), "Oceanodroma castro", Bulwer's petrel ("Bulweria bulwerii"), the brown booby ("Sula leucogaster") (50 pairs between 1986 and 1990) and "Phaethon aethereus" (only 5-10 couples between 1986 and 1990). Also there is a subspecies of the Peregrine falcon named "madens", discovered in the mid-1960s with only 15 to 20 pairs.