. The Canadian field-naturalist. Natural history. 36 The Canadian Field-Naturalist* Vol. 117 There were no significant differences between sexes in age class distribution, so sexes were pooled. Forty-two and 81 Mink were used for Idaho and Alaska samples, respectively. Results and Discussion Of 42 Mink from Idaho, 17 were adults (>1 year), for a juvenile:adult ratio of :1. In the Alaska sam- ple, 45 of 81 animals were adults (:1 ratio) (Table 1). The oldest animal in both populations was a sin- gle four-year-old, confirming reports of Mitchell (1961) in Montana, Gerell (1971) in Swed
. The Canadian field-naturalist. Natural history. 36 The Canadian Field-Naturalist* Vol. 117 There were no significant differences between sexes in age class distribution, so sexes were pooled. Forty-two and 81 Mink were used for Idaho and Alaska samples, respectively. Results and Discussion Of 42 Mink from Idaho, 17 were adults (>1 year), for a juvenile:adult ratio of :1. In the Alaska sam- ple, 45 of 81 animals were adults (:1 ratio) (Table 1). The oldest animal in both populations was a sin- gle four-year-old, confirming reports of Mitchell (1961) in Montana, Gerell (1971) in Sweden, and Askins and Chapman (1984) in Maryland that popu- lation turnover largely occurred during a three-year period. Mitchell (1958) compared ages of Mink in intensively harvested areas versus unharvested areas, and reported dramatically different demographic parameters (juvenile:adult ratios of :1, and :1, respectively). In an attempt to clarify data reported by Mitchell (1958), and to compare those data with my own, I have assumed that his "adult" animals were all between the ages of 1 and 3 years. In the Idaho study, I characterized Mink harvest as moderate; this harvest had been occurring for more than a decade prior to the investigation, and contin- ued throughout the 1977-1980 study. Mink were common, but I assumed populations were below car- rying capacity. In the Alaska investigation, trappers incidentally caught Mink in sets primarily designed for American Marten {Martes americana) and I judged their effects on Mink populations negligible. Because Marten did not exist on islands over most of the area, Mink harvests had been light prior to this investigation for at least five years. Thus, harvest pressures were assumed to be extremely light, and Mink existed at or near carrying capacity. Comparison of age structure among populations (Figure 1) suggests that furbearer managers may be able to use age structure data as an indicator of the effects of harves
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