Jan. 4. 4 mi. SE Gadsden, 120', Yuma Co., Ariz. Had cut a great deal in this thicket and the ground was strewn with broken branches. The terrain was excellent for wood rat nests, and the sign was abundant. Set rat traps at 5 nests. Skim- mmed p.m. Jan. 5. Van traps. 3 Neotoma, 1 Dipodomys deserti, 3 Perognathus penicillatus, 1 Onychomys torridus, and 11 Peromyscus maniculatus. Skinned 2 a.m. Reset trap lines p.m. On one time where I was resetting traps, heard a scraping noise in the sand, and saw a Utillus tetricandrus with one of my mouse traps over his head, rolling in the sand. Secured the specimen. Sibley came up later and called up a pair of horned owls with- in easy seeing distance. Skinned p.m. Jan. 6. Van traps a.m. 8 Peromyscus, 9 Perognathus, 2 Dipodomys deserti, 2 Neotoma alligula, 1 Onychomys torridus. 1 Neotoma was torn up and the abdomen eaten. An 1 Perognathus was bodily torn up about the head. Perognathus and Dipodomys are confined to the sand dunes, Neotoma to the mesquite thickets, and Peromyscus is everywhere. Only a few Peromyscus were caught on the dunes today, I were outnumbered there by Perognathus. Vice versa yesterday. Evidently I trapped off most of the Peromyscus from the dunes yesterday. Went to Yuma in p.m. Skinned after supper.