Berkeley, GT 1942. Itinerary Apr. 5 Mud Creeks morning the rain settled down to a steady, moderate fall. We went out after our traps about 7 AM. Seventeen traps, which I set on the hill just above camp in the same habitat of Artemisia as last night, yielded 1 Microtus and 2 Peromyscus californicus. We had set out 114 traps about ½ mile down the road near the lettuce fields. We ran traplines(1) along a fence enclosing chaparral with the ground between road and fence recently plowed, (2) inside the fence in dense wet chaparral and (3) on hillside of drier chaparral. The base of the hill was shady live oak habitat with a thick undergrowth of poison oak, bracken fern, Artemesia, Baccharis , blackberry, elderberry, snowberry, coffeeberry, and monkey flower. In many places this was 10 feet high and mostly all at least head height. The soil of the hillside is soft black humus, only slightly sandy. The growth of on the west-facing slope of the hill was less dense and less tall with more Artemesia. At the base of the hill and along the fence we set 87 traps of which 16 were sprung without a catch, the others yielding 18 Peromyscus californicus, 2 Peromyscus maniculatus , 1 Microtus californicus, 1 Sorex , and one salamander. The catch on the hill consisted of 3 Peromyscus californicus , 1 Peromyscus maniculatus , and 1 Sorex . Here 27 traps were set, of which 3 were sprung without a catch. It is probable that heavy rains last night set off some of our trap.