Status and distribution of Fea's Petrel, Bulwer's Petrel, Manx Shearwater,little shearwater and band-rumped Storm-petrel in the Azores archipelago

This paper reports the first comprehensive surveys of Fea's Petrel (Pterodr oma feae), Bulwer's Petrel (Bulweria bulwerii), Manx Shearwater (Puffinus p uffinus), Little Shearwater (Puffinus assimilis baroli) and two temporally- segregated forms of Band-rumped Storm-petrel (Oceanodroma castro) in the wh ole Azores archipelago, conducted from 1996 to 1998. Listening to nocturnal vocalizations was the main sun ey method. Breeding of Fea's Petrel was not confirmed and new sites of Bulwer's Petrel were not found (previous status : one site, 50 pairs), but previously undocumented colonies were identified for the remaining species. Manx Shearwater occurred in four colonies with 115-235 pairs (previous status: probable breeder),Little Shearwater occurre d in 28 colonies with 840-1,530 pairs (previously: four locations, >150 pai rs), hot-season Band-rumped Storm-petrels occurred in 5 colonies with 250-3 00 pairs (previously: two locations, 200 pairs) and cool-season Band-rumped Storm-petrels were found in eight locations with 665-740 pairs (previously : three locations, 600 pairs). Most colonies were confined to precipitous c liffs and islets, which may be a result of predation threats by introduced mammals. Although these surveys provided a valuable revision of the status and distribution for these species of conservation concern, further survey work is warranted and target areas are indicated. We discuss the potential and limitations of listening for nocturnal vocalizations as a method to sun ev and monitor shearwater and petrel populations in inaccessible habitats.