The Arizona Game and Fish Department and the USDA Forest Service announced the results of the fall 2007 Mount Graham red squirrel survey today. Biologists estimate that a range of 299 (plus or minus 11) Mount Graham red squirrels currently occupy the Pinaleno Mountain range, also known as Mount Graham. These results are higher than the fall 2006 estimate of 276 (plus or minus 12) 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.

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 seven years (2001-2007) 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.