Northern Idaho ground squirrel population monitoring progress report for the 2010 field season

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Population monitoring for the federally threatened northern Idaho ground squirrel (Urocitellus brunneus brunneus, formerly Spermophilus brunneus brunneus; NIDGS) occurred during April through July 2010. The spring was unusually cold, rainy, snowy, and windy; it rained or snowed 30 days during our prime monitoring period of 5 April – 5 June. This kept us from completing surveys at all sites and affected counts at many sites we did visit. We examined demography and population trends at all 5 of the long-term monitoring sites. We live-trapped and released 114 adults and yearlings, substantially fewer than 2008 and 2009. Resulting modeled population estimates showed downward trends at two sites and low but stable numbers at two others, compared to past years. We also live-trapped at 2 additional sites to establish baseline data on squirrels adjacent to treatment sites for a habitat study initiated by the University of Idaho and to collect fecal samples for future diet study analyses.
Overall, the outlook for NIDGS remained stable in 2010. NIDGS occupied 56 sites, an increase over past years even with consolidation of sites to better reflect spatial relationships. The population estimate of 1,560 adults and yearlings was lower than 2009, but 6 sites known to have squirrels in 2009 were not visited in 2010 because of weather. Numbers were essentially the same as 2009 when comparing just those sites surveyed both years. Half of the sites supported <20 adults and yearlings. The proportion of sites on federally managed land decreased as the overall number of sites increased. This changing distribution across ownerships has implications for recovery, as partnerships with private landowners become more important.

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ELECTRONIC FILE - Zoology, Mammals

Cooperative Agreement No. 14420-6-J036