Population Trends of the
Mount Graham Red Squirrel


The Mount Graham Red Squirrel Monitoring Program (RSMP) conducts a quarterly census of the squirrel population within their monitored areas (all areas within 300m of the Mount Graham International Observatory and Access road; and two non-construction, control areas).  Biologists visit each midden site, examine it for evidence of red squirrel activity, and observe for extended periods of time to determine the presence of a resident squirrel.  Multiple visits are often made to midden sites to verify the residency of a squirrel, and attempt to determine its sex, age, and any natural marks or tags.

Throughout the course of this study slight differences in red squirrel numbers between the construction and non-construction study areas have been observed.  However, many natural disturbances such as fire, insect outbreaks, and fluctuations of food resources have caused significant declines in population size of these monitored squirrels.  Additional research is, therefore, needed to isolate these factors in order to determine what impacts telescope construction and operation may have on the squirrel population.

The following graph represents data collected in the RSMP monitored areas only.  If you are interested in total population estimates of the Mount Graham red squirrel we suggest contacting the Arizona Game and Fish Department which, in conjunction with the U. S. Fish and Wildlife Service, the U. S. Forest Service and The University of Arizona, conducts a mountain wide census twice per year.


Click here to view the raw data.


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This site is maintained by the Mt. Graham Biology Program - The University of Arizona.

If you have any questions or comments please email us at:RSMP@ag.arizona.edu