clear how fai* north Cook sailed, but no other 

 summer observers have encountered Ivory 

 Gulls at sea although all have come in contact 

 with the pack ice. Both Nelson (1883) and 

 Jacques (1930) observed breeding birds at 

 Herald Island. 



We observed few Ivorj' Gulls in the Barrow 

 area although they wei-e common near Wain- 

 wright (fig. 19). In the study area this species 

 was largely associated with the ice (table IV, 

 fig. 20) . Large flocks assembled at stations with 

 smaller groups being observed on transects 

 (table III). The marine science technicians saw 

 a pair of what they tentatively identified as 

 this species at 71°25'N, 167° 13' W on 17 Sep- 

 tember when ice surrounded the ship. None was 

 observed south of the .study area. Immatures 

 constituted roughly one quarter of all individ- 

 uals observed. 



Outside the breeding season, the Ivory Gull 

 is thought to be primarily a scavenger feeding 

 to a great extent on the kills of Polar Bears. 

 The only scavenging we saw, other than some 

 feeding on the ship's garbage, were small flocks 

 observed over whales on two occasions and a 

 single individual feeding on Walrus dung on the 

 ice. The primary methods of obtaining food we 

 observed were hovering and contact dipping 

 near ice cakes. Fish appear to be the primary 

 food obtained in this way since Arctic Cod 

 constituted the bulk of the food items found in 

 stomachs (table V). One individual had eaten 

 a pyrid ascidian, either Halocyntbia sp. or 

 Bottenia sp. Six of the 14 specimens collected 

 were immatures (table II). Mallophaga from 

 this species v/ere identified as Saemundssonia 

 lari (0. Fabricius 1780). 



Black-legged Kittiwake (Rissa fridactyla) 



The Black-legged Kittiwake breeds through- 

 out the Chukchi Sea wherever suitable nesting 

 cliffs exist, almost as far north as Barrow. It 

 was the third most abundant species at the 

 Cape Thompson cliffs in 1960 with 13,000 

 breeding pairs (Swartz, 1966). This most 

 pelagic of all gulls feeds far out to sea in all 

 seasons. Summer observers have found it com- 

 mon in the Chukchi. Nelson (1883) saw it in 

 all parts of the arctic with large numbers 

 present at Herald Island and smaller numbers 

 at Wrangel Island. Jacques (1930) found it 

 sometimes abundant throughout the Arctic. 



Swartz (1967) reported it most common near 

 the breeding cliffs in the Point Hope-Cape 

 Thompson area. The species probably winters 

 at sea from the Aleutians southward but there 

 is no evidence of mass migration. 



Kittiwakes were present in small numbers in 

 the area of Barrow and along the coast to the 

 study area. In the study area it was the least 

 common of the major species of gulls we ob- 

 served (fig. 23) and tended to flock less than 

 the others (table III). It showed affinity for 

 areas of open water (table IV) and in the Bering 

 Strait it was seen throughout the day 18 Octo- 

 ber (fig. 22). Approximately three quarters of 

 all individuals observed throughout the cruise 

 were immatures. 



Plunging to the surface was the most com- 

 mon mode of feeding observed for this species. 

 On the few occasions when it was observed in 

 ice areas, individuals wei'e seen feeding while 

 hovering near ice cakes. The stomachs of the 

 four specimens collected (table II) contained 

 remnants of Arctic Cod (table V) . Mallophaga 

 from this species were identified as Saemunds- 

 sonia lari (0. Fabricius 1780). 



Ross' Gull (Rhodostethia rosea) 



The breeding grounds of Ross' Gull are re- 

 stricted to the Kolyma and Indigirka River 

 deltas (62°27' to 70°30'N, 142° to 162° E) in 

 northern Siberia. There are scattered records 

 of pairs of birds elsewhere in the arctic during 

 the spring and summer but only one definite 

 breeding record outside of northern Siberia: a 

 nest found on Disko Bay in western Greenland 

 (Dalgleish, 1886). Two pairs were taken by 

 Brower near the Seahorse Islands southwest 

 of Barrow on 16 June 193.5. All four were in 

 breeding plumage though none had bare brood 

 patches. There are also records of single birds 

 taken in the summer on the arctic coast 

 (Bailey, 1948). Jacques (1930) is the only 

 summer observer to encounter this species in 

 the Chukchi. He saw a total of eight birds in 

 mid and late August; all were north of 70° N 

 near Herald and Wrangel Islands. In the fall, 

 Ross' Gulls migrate east through the Chukchi 

 Sea but there are few records for the Bering 

 Sea. They are commonly observed at Barrow 

 in September and October, and on the basis of 

 these observations the wintering grounds are 

 thought to lie to the east of Barrow. They 



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