R. B. Hamilton 1965 Stercorarius pomarinus June 18 About 10 pair of jaeger were seen from Bezel Ridge. One pair was seen copulating. The M mounted the F 9 several times emitting a yipping sound. The F was crouched on the ground. The M moved her tail to the side to effect contact. Contact was seen several times. June 19 About 15 jaeger were observed resting in Family Lagoons and were not territorial. The rest of the jaegers were scattered and appeared to be territorial. June 20 At least 3 large groups of non-territorial birds were observed in Family Lagoon and South Split Lagoon. These flocks consisted of a total of about 80 birds. The other birds were scattered as pairs about the tundra. The most described previously was checked and it contained two eggs. It was checked on the 19th and contained only one egg. The note given by the male in defence of the nest was again heard. It is a trill note with all 3 notes sounded in a total time of about 1 sec. This note seems higher in pitch than the notes normally heard and not as nasal. It was sent at a "nzzzz - nzzzz - nzzzz". The male of the nesting pair was observed for about 10 minutes in a territorial dispute with a neighbouring female. This consisted mostly of the birds chasing each other and then turning around and reversing roles. Some yipping notes were heard. The place where reversal of dominance seemed to occur was about 30 yds. short S at the Islaug nest.