J.R.Alcorn 1940. Microtus 4mi.W Fort Howe R.S., 4000ft, Powder River Co., Montana June 14, 1940. When I first arrived in camp I noted signs (Cut grass and a few runs) of Microtus along the small stream created by dripping spring where we are camped. For several nights I was unable to trap any of these animals near this location. Yesterday I noted many runs of some small mammal among the dry, E. sloping, grassy land about 100 feet from the nearest water. Some large timbers (12x12) were loosely scattered about over a 50 foot square area. It was in near these timbers that most runs were seen. Droppings in the runs did not look fresh and I noted that grass was starting to grow in the runs in many places. These facts lead me to believe that the mice, for the most part, had abandoned the location or possibly some were killed by