Birds in Bering and Chukchi Seas — Swartz 
339 
Fig. 12. Abundance, distribution, and movements of Glaucous Gulls {open and half open circles ) and 
Herring Gulls {black circles). Numbers and direction of flight of Glaucous Gulls indicated by size of sym- 
bols and direction of vectors; smallest circle, 1-5; °, 6-10; 0> 11-20; 3 > 21-40; Q, more than 150. C 
indicates circling, F indicates following the ship, and X indicates birds on the water. 
Fig. 13. Abundance, distribution, and movements of Black-legged Kittiwakes. Numbers and direction of 
flight are indicated by size of symbols and length and direction of vectors: smaller circle, 1-5; °, 11-20; 
shortest arrow, 1-5; -» 6-10; » 11-20; C indicates circling and X indicates birds on the water. 
Unidentified Jaeger 
Jaegers were seen but could not be identified 
on 15 occasions. These observations were 
widely scattered but all were north of 67 °N 
(Fig. 9). 
Glaucous Gull (Larus hyperboreus) 
Adult and immature Glaucous Gulls were 
most abundant at the cliffs and beaches where 
they fed extensively on the eggs and chicks of 
other species, especially murres. They were 
seen frequently to about 25 miles offshore and 
only occasionally at greater distances (Figs. 12 
and 14). This species and, to a lesser extent, 
kittiwakes often followed the ship for up to 
several hours at a time. Both species fed on 
garbage thrown overboard. Although some 
tendency to fly into the wind was observed 
from shore and from the ship, no large move- 
ments of Glaucous Gulls in response to wind 
were evident. Such movements by larids have 
been observed by other authors, however (e.g., 
Harrison, 1955:109-110). 
Herring Gull (Larus argentatus) 
Two doubtful sightings of immature birds 
(possibly the same bird sighted at different 
hours) were made 16-18 miles west northwest 
of Cape Thompson on August 24. Groups of 
two, four, and three individuals were sighted 
near shore in the vicinity of Port Clarence (Fig. 
12). All Herring Gulls sighted were immature. 
Black-legged Kittiwake (Rissa tridactyla) 
Both adult and immature kittiwakes were 
common on the open ocean (Fig. 13). Adults 
were often in winter plumage. The adults in 
breeding plumage and immatures were most 
abundant near the nesting cliffs, but the radius 
of their daily movements from the cliffs is not 
