-9- Black-winged Petrel (Pterodroma hypoleuca) Black-wings were recorded regularly in the southern hemisphere. These birds probably represent individuals that have finished their breeding cycle early, or have had nest failures. Kermadec Petrel (Pterodroma neglecta) Kermadec Petrels were recorded further north than any other tropical species of Pterodroma. Sightings were usually of single birds and were distributed over four areas. Color-phases recorded are: 1 dark, 6 light with chest bands in the northern hemisphere, 3 light without chest bands in the southern hemisphere. The remaining 4 birds are a result of an estimate on a feeding flock of Pterodroma. Murphy Petrel (Pterodroma ultima) This species was recorded with some regularity between 10°S and 15°S. Its uniform light brown pattern, typical Pterodroma shape and flight, readily identify it once other dark shearwater/petrels are known. In size it appears between the Kermadec Petrel and the Juan Fernandez Petrels although the physiognomy resembles P. externa. Cook Petrel (Pterodroma cookii) This cold water species of Pterodroma was found most abundantly along the convergent zone of the California current and the warm water mass in the Cape San Lu area. Its flight, color pattern and white wing stripe aid in identification. White-winged Petrel (Pterodroma leucoptera) This species was abundant in the south equatorial counter current. The population probably represents post-breeding birds from Mas Afuerra. The overlapping pelagic ranges of Pterodroma leucoptera and Pterodroma hypoleuca indicates a difference in feeding habitats which is as yet unknown. A careful analysis of environment and stomach contents of these two species should aid in answering questions on basic ecological concepts that would further the understanding of all species in the pelagic habitat.