W. B. Davis 1935 Salmon Creek, 8 mi. W Rogerson, Twin Falls County, Idaho. May 14. I visited my traps this morning about 6 A.M. The sun was up an hour, but the piercing cold accompanied by a stiff SE breeze preserved all specimens. In an area of loose boulders amongst Artemisia I took three Perognathus parvus; amongst the rocky cliffs Peromyscus (10) were common, and in this same type of habitat I took one Reithrodontys. Five Dipodomys were taken in the semi-sandy sage covered areas. The following were my takes: Dipodomys ordi. 5 ♀ adults. Perognathus parvus 1♂ 2♀ " Peromyscus maniculatus 4♂ 6♂ " Peromyscus ? 1♂ " Reithrodonmys 1♀ " Stayed in camp until about 4:00 P.M. putting up specimens, then went down into the canyon below the dam. Here the canyon walls are nearly vertical with innumerable jute holes which offer excellent nesting sites for Swifts, Swallows, Hawks and Owls. Located the nesting site of a Western Redtail and a Horned.