Birds Found on the Arctic Slope of Northern Alaska

by James W. Bee

In the period July 8-15, 1951, four adult males at Topagaruk and Kaolak River averaged 31(28-33) grams in weight. Their testes [averaged] 2.3(2-3) mm long. A female (July 8) weighed 37 grams. Her largest ovum was 2 mm in diameter. A juvenile from Kaolak River (July 16) was 176 mm long and weighed 35 grams. Young northern phalaropes at Kaolak River (July 12-18, 1951) were more numerous than at Topagaruk (July 4-10, 1951) and were almost the size of adults. On July 15, on a four hour field trip, we counted 24 individuals including adults and juveniles. On this date the juveniles were almost ready for flight. At Kaolak (July 22, 1951) a young bird 212 millimeters in length was flying and feeding alone. In our seven day stay at Teshekpuk Lake only one northern phalarope was seen. It was near camp on August 3, 1951. Between Birnirk and Point Barrow (Aug. 25, 1952), approximately 3000 northern phalaropes had collected on fresh water ponds, salt water lagoons and on the Arctic Ocean. Many of them were feeding while others were nesting on matted green mosses bordering ponds. Their habit of spinning in water was noted. Those feeding on the Arctic Ocean were on the relatively smooth water immediately beyond the point where the breakers formed. On September 11, at Point Barrow, we did not see the species.

Stercorarius pomarinus (Temminck): Pomarine jaeger.—At Birnirk (June 14, 1952) while snow still covered most of the ground, pomarine jaegers hunted for lemmings by flying approximately 20 feet above the tundra and occasionally hovering. On June 15, one had eaten parts of two large lemmings caught in traps along the edge of a snow-bound lake. On June 17, these birds were preying on live lemming and swallowing them whole. One flew 50 meters with a brown lemming in its mouth and after alighting, consumed it. The backs of several lemmings caught in traps had scars probably made by jaegers or conceivably by snowy owls. West of Salt Water Lagoon (June 17, 1952), 12 jaegers were counted with the aid of a 6 × 30 power binocular in a 90° arc to the southward. Three snowy owls also were hunting in this area. In traveling one and three-eighths miles south by east from Barrow Village on June 20, 1952, we counted eight single pomarine jaegers in the air and on the return trip the same day, five pomarine jaegers (one was dead, another was resting on a lake and 3 were in flight).

At Point Barrow (June 21, 1952) two pomarine jaegers left the land and flew north out of sight over the Arctic Ocean. At a point 9⁄10 mile east and 4⁄5 mile north of Barrow Village (June 23, 1952) we observed a pomarine jaeger cruising three feet above ground. It dropped to the tundra and picked up a lemming by its back and after adjusting the lemming swallowed it tail first. On a lake one mile southwest of the Arctic Research Laboratory a group of six and two pairs all facing into the wind were resting on ice. In an area of 240 acres (outlined by the tripod communication line to the west, "Y" line to east, and row of 50 gallon drums following the ground line to south), we counted 19 pomarine jaegers in groups of from one to four or one per 12 square acres; one snowy owl was in the area.

At Kaolak River (July 12-18, 1951) pomarine jaegers were the second most common jaeger in the area. In walking for four hours on July 15, two pairs were noted. Ordinarily, however, these birds are seen singly not in pairs. At Lake Schrader (July 23-31, 1952) pomarine jaegers were active both day and night, especially at night. At Barrier Lake (Aug. 2, 1951) two pomarine jaegers flew close together along the edge of the south end of the lake. As they left the lake and flew over the extensive marsh to the east they separated and flew as single individuals. On August 4, a pomarine jaeger was chasing an Arctic loon that had a fish in its bill. On August 10, 1951, a single pomarine jaeger was noted at Chandler Lake. As late as September 7, 1952, one half mile south of the Arctic Research Laboratory, seven pomarine jaegers were foraging for brown lemmings.

Stercorarius parasiticus (Linnaeus): Parasitic jaeger.—Specimens, 3: Topagaruk River, 155°48', 70°34, 10 ft., 2, Nos. 30732-30733, ad. females, July 6, 8, 1951; Kaolak, 160°14'51", 69°56'00", 178 ft., 1, No. 30731, ad. male, July 21, 1951.

At Topagaruk (July 5-10, 1951) parasitic jaegers ranged over nearly all plant and animal associations, but flew more frequently over polygons with low centers than elsewhere. Data on two adult females, shot on July 6 and 8, in that order are as follows: weight, 525, 320 grams; largest ovum, 3, 1 mm; length of ovary——, 5.5 mm. The bird killed on July 6 was in the black color phase.

At Kaolak River (July 12-18, 1951) the parasitic jaeger was the least common of the three species of jaegers.

At Kaolak (July 21-27, 1951) two birds nested near camp while others passed through the area. These passing birds generally were seen singly or in pairs; long-tailed jaegers commonly are in groups of four or five. The parasitic jaegers were not so noisy nor so much given to chasing others of their own species as were long-tailed jaegers. Several single birds hunted in areas of sedges and grasses that yielded lemmings. On July 21, a parasitic jaeger was flying with three glaucous gulls, and demonstrating its usual flight tactics of gliding, climbing and swooping as it accompanied the gulls. An adult male shot on July 21, weighed 460 grams.

On alluvial outwash at the southwest end of Lake Schrader (July 27, 1952) a male and female parasitic jaeger defended their territory by diving at us. Periodically both birds alighted approximately 60 feet away and each pretended to have a crippled wing for approximately a minute. The female acted as if herding the young but was not. On each of our daily inspections an adult defended the area. In a period of four days the area defended was shifted approximately 1⁄5 of a mile south in the marsh area adjacent to the lake. Parasitic jaegers were noted in the Lake Schrader area from July 23 to July 31 inclusive.

At Barrier Lake (July 30, 1951) two parasitic jaegers were harassing a glaucous gull that responded as if being attacked by a hawk. The plunging of the jaeger continued while the gull was flying 300 feet horizontally. One other jaeger chased a glaucous gull for one-fourth of a mile and finally having caught up with it dove at the gull several times, each time almost making contact. From our camp on Barrier Lake (July 29-Aug. 4, 1951) we watched parasitic jaegers hunt along the south end of the lake, following precisely the edge of the water. The wind drove debris to the south end of the lake. The long-tailed jaeger was the more numerous here; it flew along ridges and over marshes. On July 30, a single jaeger flew over the lake and after hovering above a young Arctic loon, which had strayed from its parent, dove down and picked it up. Three other parasitic jaegers arrived and competed for the prey.