The average length and weight of six adult males and adult females from Gavia Lake and Driftwood (Aug. 23-29, 1952) are, respectively, as follows: 153(148-165) mm and 19(18-21) grams. One female from Umiat shot on June 30, 1952, weighed 22 grams. The ovary was 5 mm long and the largest ovum was 1 mm in diameter. At Umiat (June 30, 1952) a bluethroat was captured in one of 200 traps placed around the edge of a small lake. The trap that held the bird was in a soil fracture 15 centimeters in depth in an area that supported alder, willow, birch and ericaceous shrubs. At Driftwood, a bluethroat was caught on August 28, 1952, in a trap set among willows. +Phylloscopus borealis kennicotti+ (Baird): Arctic warbler.--On the north side of the valley at Umiat on June 27, 1952, willow warblers sang loudly and continually in accompaniment with white-crowned sparrows, tree sparrows, gray-cheeked thrushes and bluethroats. +Motacilla flava tschutschensis+ Gmelin: Yellow-wagtail.--Specimens, 2: Kaolak, 160 deg.14'51", 69 deg.56'00", 178 ft., 1, No. 30757, ad. female, July 27, 1951; Umiat, 152 deg.09'30", 67 deg.22'08", 352 ft., 1, No. 31329, ad. female, June 26, 1952. At Umiat on June 25, 1952, a nest of the wagtail was on the side of a mound of earth three feet high. The nest, 130 mm in diameter and 14 grams in weight, was completely protected overhead. The lower half of the cup, 59 mm in diameter and 35 mm in depth, was lined (3 mm in thickness) with hair of caribou and brown lemming; the upper half was of feathers. Beneath the lining of the cup was 38 mm of moss. The outer nest, 33 mm in thickness, was, of coarse stems of grasses and other material. The nest was not so carefully constructed nor so well insulated as nests of tree sparrows, longspurs and snow buntings; it lacked the fine yellow grasses and symmetrical lamination of the materials and had more large chunks of material thus producing an irregular shape. Both male and female remained in the air directly overhead for 15 minutes as we examined the nest and then followed us for 100 yards as we left the area. An adult male shot on June 26, was incubating four eggs. He was 165 mm in length and weighed 19 grams. On July 27, 1951, seven days after our arrival at Kaolak, a male and female were seen for the first time. They flew back and forth overhead and called as if defending a territory but probably were not as we had been through this same area many times without either seeing or hearing these birds; also the female's ovary was undeveloped. +Anthus spinoletta rubescens+ (Tunstall): Water pipit.--Specimens, 3: Mount Mary, S end Lake Peters, 145 deg.10'02", 69 deg.20'30", 2920 ft., 1, No. 31330, juv. female, August 3, 1952; Wahoo Lake, 146 deg.58', 69 deg.08', 2350 ft., 2, Nos. 31331, female, July 7, 1952 and 31332, ad. male, July 8, 1952.