December 1964 - BCF cruise White-necked Petrel The apparent increase in numbers of this race from four in November to 13 in December might be the result of confusion with fairly white necked Juan Fernandez Petrels, although it is not too likely. A slight concentration was noted in the southeastern corner of the area. Juan Fernandez Petrel Numbers of this race dropped 48°/o from 297 in November to 156 in December. Presumably numbers will decrease still further next month as the birds' breeding season approaches. The southeastern corner of the area had clearly the highest density of these birds. Three were seen within 5 miles of Oahu. Leach's Petrel This species decreased 45°/o from 96 in November to 53 in December. Concentrations were seen in the northeast corner and in the southern end of the area. This species will probably maintain similar numbers in the area throughout the winter. The increased numbers experienced in the fall and spring reflect migration peaks, while the lower winter plateau represents a wintering population in all likelihood. Fork-tailed Petrel One bird doubtless of this species was observed on 7 December. This species may be of regular occurrence in the area in winter but due to the extreme difficulty in clear observation of this species few ill ever be recorded.