5 Herring Gull distribution which shows a fairly progressive trend to push southward Glaucous-wings show no discernible tendency to favor the northern sections of the Grid. Herring Gull Larus argentatus # Obs. = 258 The most constant and conspicuous element of the Grid fauna was groups of this gull following the ship. .6 .5 .1 .5 .3 .4 "Linear density" .1 .4 .1 by section The northern two-thirds of the Grid has densities approximately double that of the southern third. Sixty-eight percent of the aged birds were adults. This is nearly the same as the previous survey (EGS 19; 63 percent), but both recent surveys have a much higher per- centage of adults than that recorded in late November (EGS # 17; 3 of 18 birds: 17 percent). The age distribution (adults vs. nonadults) is not uniform over the Grid; adults are not as abundant in the southern third. Third Percent adults. North 73 Center 79 South 43 Black-legged Kittiwake Rissa tridactyla # Obs. = 153 .17 .38 .28 .17 .43 .36 0 0 .05 Birds per linear mile Total Grid numbers have increased regularly over the last three surveys: EGS # Total Obs. Late Nov. 17 0 Early Dec. 18 4 Late Dec. 19 80 Early Jan. 20 153 This survey's data suggest that the bulk of the Kittiwakes is pushing southeastward through the Grid concentrated in a fairly well- defined "tongue." At the north end of the Grid the highest density is located in the center third; in the center latitudes the concentration is shifted to the two eastern thirds (V and W) and in the south latitudes the only section with Kittiwakes recorded is the easternmost (Z). Per- haps numbers increase again directly to the east of "Z" but no observa- tions were taken over this region.