Salmon Creek, 8 mi. W Rogerson, Irwin Falls Co., Idaho, May 13, Spilogale, and Porcupine; the last in the canyon below the dam. Irwin found a nest of the Raven today on a rocky ledge about two miles south of camp on the east side of the reservoir. Six eggs reported. I have failed so far to find any indication of the presence of Thomomys and Citellus. Mr. Molin. reported that the ground squirrels were quite common west of the creek around the ranches. Aldrich reported that he saw a chipmunk of some sort on the west side of the canyon. This canyon -- and reservoir appears to have some effect as a barrier in this particular area, though it is quite possible that in many places the dry stream of summer allowed crossing.