At Topagaruk (July 5-10, 1952) adults of this species were the fourth most common bird, representing four per cent of the avian population. They were near lakes among polygons some of which had low centers whereas others had high centers. One bird had a nest and four eggs approximately 150 feet from an oil derrick, surrounded on all sides by the tracks of vehicles. This bird feigned injury at the nest notably more than did Baird's sandpipers that inhabited undisturbed tundra beyond. Three adult males, shot at Topagaruk (July 7-10, 1951), averaged 44(42-47) grams in weight and had testes averaging 3.5(3.0-4.5) mm long. Two females, collected in the same period and at the same place averaged 44 grams in weight. The largest ovum was one mm in diameter and the largest ovary three mm long.
Other occurrences were: Kaolak River, July 12-18, 1951 (four juveniles observed in one four hour field trip July 15); Lake Schrader, July 24-28, 1952; Point Barrow, July 27, 1951 (most common shore-bird at fresh-water ponds adjacent to the Arctic Ocean); 2 mi. S Wahoo Lake, on a high divide between the Ivashak and Sadlerochit rivers, July 8, 1952; Lake Schrader, July 23-31, 1952 (active at all hours); S end Lake Peters, August 1 and 2 but not seen there later.
+Erolia alpina pacifica+ (Coues): Dunlin.--Specimens, 21: Barrier Lake, NE Teshekpuk Lake, 153°05'40", 70°39'40", 8 ft., 1, No. 30661, ad. male, Aug. 1, 1951; Topagaruk River, 155°48', 70°34', 10 ft., 20, Nos. 30662-30681, 12 ad. males and 8 ad. females, July 6-9, 1951.
Specimens shot at Topagaruk River (July 6-9, 1951) yielded weights of 57(53-64) grams for eleven adult males and 59(55-65) grams for six females. Testes were 3.5(2.0-5.0) mm long, the largest ova were 1.2(.5-2.0) mm, and ovaries were 3.5(3.0-4.0) mm long. An adult female from Teshekpuk Lake (August 1, 1951) weighed 48 grams. Her largest ovum was one mm in diameter and the ovary was 3.5 mm long.
At Topagaruk we observed the species every day (July 5-10, 1951) and on July 7, located a nest and four eggs. Each of the seven times that the brooding female was approached she left the nest when we were approximately 80 feet away and she flew approximately 150 feet before alighting at which time she called. The call resembled that of the western grebe. The wary nature of this sandpiper was in contrast to that of the other smaller shore-birds; they left the nest only when almost stepped on. On July 9, the nest still held four eggs. Adults were the fifth most common bird and made up three per cent of the avian population. They frequented polygons having low centers adjacent to stabilized lakes. At Kaolak River (July 17, 1951) a dunlin was feeding and flying with a group of four semipalmated sandpipers. At Point Barrow (July 27, 1951) dunlins were congregating in small groups at ponds and small lakes adjacent to the Arctic Ocean. At Barrier Lake (July 29-Aug. 4, 1951) three dunlins fed in the area but did not show territorial behavior.