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The Arizona Game and Fish Department and the USDA Forest Service announced on Oct. 26 the results of the fall 2009 Mount Graham red squirrel survey. Biologists estimate that a range of 250 (plus or minus 11) Mount Graham red squirrels currently occupy the Pinaleño Mountain range, also known as Mount Graham. These results are lower than the fall 2008 estimate of 263 (plus or minus 11) squirrels.
The red squirrel survey is conducted by visiting a random number of known middens (areas where red squirrels store or cache their cones). The activity rate is then extrapolated across the total number of known middens to determine the population estimate. While spring surveys provide us with a look at recruitment numbers, activity is often difficult to detect during the spring. This can result in fluctuating (variable) estimates. Because cached cones are easier to detect during the fall survey, fall population estimates may be easier to compare from year to year. No spring survey was conducted in 2009.
Although none of the population estimates statistically indicate a trend in the population, our estimates show two groups of figures with a spike during 1998-2000. It is apparent that Mount Graham red squirrels had a population of around 350 individuals from 1991-1997, and over the last nine years (2001-2009) the number has fallen to somewhere around 250 individuals. A combination of drought, poor cone crops, fires, and insects may have caused reductions to the population. As with other small mammals, biologists are confident, that given the right conditions, Mount Graham red squirrels may be able to rebound as shown during 1998-2000.