Survival, Causes of Mortality, and Reproduction in the American Marten in Northeastern Oregon

Abstract

Survival rates, causes of mortality, and reproduction in the American marten (Martes americana) were determined in northeastern Oregon from 1994 until 1997 with radiocollared martens. The probability of survival of martens >9 mo old was 0.55 for 1 yr, 0.37 for 2 yr, 0.22 for 3 yr, and 0.15 for 4 yr. The mean annual probability of survival was 0.63 for 4 yr. Twenty-two of 35 radiocollared martens died. Of the 18 martens killed by predators, 8 were killed by bobcats (Lynx rufus), 4 by raptors, 4 by martens, and 2 by coyotes (Canis latrans), based on necropsies and circumstantial evidence at kills. Three martens died of exposure and 1 of collar entrapment. Of 13 reproductive efforts, 4 females weaned 21 kit, 8 efforts failed, and the outcome of 1 was unknown. Predation of adult females prior to weaning was the source of reproductive failure for some efforts.