6 Black Storm Petrel (Oceanodroma melania) Pronounced ship followers, these birds usually showed a gradual buildup astern during the day. After a peak in the area just south of the mouth of the Gulf of California, a broad gap of some 1200 miles passed with only a single sighting. From Coast Rica to Panama, however, the birds were again present in good numbers. While I see no mention in the literature, this discontinuity suggests to me that when the breeding population returns to the breeding grounds in northern Baja, a nonbreeding segment of the population (immatures ?, first-year birds?) remains in the southern end of the species range. Least Storm Petrel Halocyptena microsoma One bird was tentatively recorded as this species on 2 June. Two "Dark- rumped" Storm Petrels seen off Panama may have been this species as well. Red-billed Tropicbird Total Observations - 6 The six birds, scattered from the second to the twelfth day, indicate the broad range and low relative numbers of this bird. Three birds were seen in conjunction with the large Manx flocks on 5 June. Birds were heard calling at sea. Brown Booby Total Observations - 118 The Brown was the first Booby to appear and high numbers were logged when close to the coast on 4 and 5 June. Many immatures, 50-75 percent, were seen in the Manx flocks, and others were found riding turtles. After a 700-mile absence, browns were again common off Coast Rica and Panama where proportionally more adults were observed. Red-footed Booby Red-feet were first logged on 7 June, but were probably present on the sixth as well, off Acapulco. No birds were seen after the ninth when a "great many" appeared. Most sightings were of non-adult birds. I did not see any white adults to my knowledge. Blue-faced Booby Total Observations - 11 Blue-faced Booby showed the same type of occurrence as the Red-foot; appearing and disappearing in the same three-day span. Most sightings were of adults. Frigatebird Species Total Observations - 28 Only one bird was observed well enough to positively identify as a Magnificent, however, all were presumed to be that species. The first bird was sighted off northern Costa Rica. Twenty of the 28 birds were seen in the Gulf of Panama.