The following measurements of juveniles show increase in size as correlated with advance of season: Topagaruk (July 6, 1951) two juveniles averaging 110 mm in length weighed 21 grams; Kaolak River (July 17, 1951) young of one family averaged 178 mm in length and another individual was 162 mm in length and weighed 38 grams; Kaolak (July 21-27, 1951) individuals in a group of nine were approximately 3/4 the size of parents and other groups were 1/3 to 2/3 the size of adults. In a brooding female 600 mm long from Topagaruk (July 8, 1951) the largest ovum was two mm in diameter. Females, averaging 650 mm long from Kaolak (July 23, 1951) had ovaries smaller than the normal size for breeding birds; the largest ovum was only 1/2 mm in diameter. Males of the same size had testes six mm in length. +Lagopus mutus nelsoni+ Stejneger: Rock ptarmigan.--Specimen, 1: Wahoo Lake, 146 deg.58', 69 deg.08', 2350 ft., No. 31309, ad. male, July 11, 1952. At Wahoo Lake (July 6, 1952), young of one brood for the first time since July 3, called continually throughout the day and part of the night. Members of three other broods, only a few days old, did not call in the same persistent way. Along a deeply eroded western outlet of Wahoo Lake there was an unusual concentration of fecal droppings, spaced approximately every two or three feet. This sheltered place offered protection from cold and winds of winter. Adults were associated with willows along creeks and on adjoining sidehills where willows gave way to open tundra. One family left the willows and the female flew back and forth behind the young as she herded them. The largest adult male seen here was shot on July 11. It was 365 mm in total length, weighed 460 grams, and had testes 7 mm long. At the south end of Lake Peters (August 14, 1952), a female and her two young, along with other kinds of birds, were attracted to our tent during snowstorms. On July 18 at Wahoo Lake, a juvenile was 200 mm in total length and weighed 100 grams whereas on August 9 at Lake Peters a juvenal male was 261 mm in length and 226 grams in weight. Rock ptarmigan were uncommon at Chandler Lake. We observed the first bird in the area on August 22, 1952, 13 days after our arrival. Droppings of the birds were only occasionally seen there. +Grus canadensis canadensis+ (Linnaeus): Sandhill crane.--In 1952, two sandhill cranes called in the river valley north of Umiat on June 24. On June 26, 27 and 28, a single bird was seen there. It remained in the general area and called occasionally. Sandhill cranes are only occasionally seen along the Colville River. A pair of these cranes was seen near Meade River on August 16, 1952, by Marvin Mangus.