Snowshoe hare pellet-decay rates and aging in different habitats

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Snowshoe hare (Lepus americanus) pellet surveys are an efficient tool for monitoring population trends, but there is no standard methodology used to conduct surveys. To assist researchers in developing protocols, we evaluated pellet-decay rates and aging in 3 snowshoe hare habitat types in Alaska during the peak and decline of the hare population from 1999–2002. We found significant differences in decay rates among habitat types and recommend measuring decay rates if pellet counts are to be compared among habitats or regions. Our experiments with known-age pellets indicated that pellets could not be aged reliably, but results from side-by-side comparisons of survey methods provided contrary evidence. Counts from uncleared plots, in which observers subjectively decided whether pellets were “new” (<1 year old), were not statistically different from counts on annually cleared plots. We evaluated 4 methods for conducting pellet surveys: 1) cleared plots with counts of “new” pellets; 2) cleared plots with counts of all pellets; 3) uncleared plots with counts of “new” pellets; 4) uncleared plots with counts of all pellets. Annual trends in pellet counts were similar using the first 3 methods, but counts from method 4 were inflated in 2002 due to a high prevalence of “old” pellets. We conclude that cleared plots are preferable to uncleared plots, and we suggest that using subjective criteria to age pellets may be useful if tallies are kept of both “new” and “old” pellets for each plot.