December 1964 - BCF cruise Herald's Petrel Six birds presumably of this species were observed, including two dark phase birds, the first to have been seen in the area. They were distributed throughout the central part of the area. Mottled Petrel Two birds, seen only imperfectly, were thought to be this species. One was flying south and the second was taking part in a feeding flock. Phoenix Petrel One bird presumably of this species was seen on 7 December near Hawaii. Bonin Island Petrel Three imperfectly observed birds seen in December were thought to be this species. Two were north of Oahu and the third was east of Hawaii. Cook's Petrel Numbers of this species decreased sharply from 268 in November to 19 in December. A slight concentration was noticed in the southern end of the area, but individuals were observed in all parts. This species is most likely heading south for its breeding season and will probably not become abundant again until early summer. Dark-rumped Petrel One bird thought to be this species was seen on 14 December toward the southeastern comes of the area, further south than any have previously been reported.