Status of the Craters of the Moon National Monument Deer Herd

Ritchie, B

Study of population status, movement patterns, and food habits of the Craters of the Moon National Monument deer population. The population status, movement patterns, and food habits of theCraters of the Moon National Monument mule deer (Odocoileus hemionus h.)population were studied April 19, 1967 to January 20, 1968. The deer population had increased slowly but steadily since the Monument was created in 1924 and numbered about 335 individuals in 1967. The herd was very productive with fawns comprising 48.5 percent of the summer population.Thirty-three deer were marked. Marked animals were identified 386 times inthe field. The herd wintered about 20 miles northeast of Monument head-quarters and Monument lands were used only as summer range. On summer range, the herd divided into two groups. One group ranged in the northern area and was rather sedentary. The other group ranged in the southern part of the Monument and made an unusual "migration" of four to eight miles during the dry part of the summer to the northern area. This movement was apparently • related to a lack of drinking water in the southern area. The deer fed mainly on browse, with bitterbrush (Purshia tridentata) being the stapleforage species. The northern part of the range was used heavily by deer and preferred browse plants there were generally hedged. Permanent transacts were established to assess range trend. It appears that the deer population will eventually have to be controlled in order to protect the natural condition of the range.