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Endangered Mount Graham red squirrel shows promising rebound

Posted November 2, 2020

Back to triple digits after wildfire caused significant habitat, species loss 


PHOENIX — Three years after their habitat was nearly wiped out by the 2017 Frye Fire in the Pinaleño Mountains of southeastern Arizona, an annual survey of the endangered Mount Graham red squirrel shows an exciting and notable increase in their population. 

The annual survey, conducted jointly by the Arizona Game and Fish Department (AZGFD), Coronado National Forest, U.S. Fish and Wildlife Service (USFWS), Arizona Center for Nature Conservation – Phoenix Zoo, and the University of Arizona, resulted in a minimum estimate of 109 squirrels. This is the first time the population has returned to the triple digits since they were severely impacted by the Frye Fire.

In 2016, there were an estimated 252 squirrels. Immediately following the Frye Fire estimates dropped to a mere 33 individuals. Typical ranges since 2000 fall between 200 and 300 squirrels.

“Mount Graham red squirrels have faced some significant, daunting challenges since their habitat was severely damaged by the Frye Fire,” said Tim Snow, AZGFD terrestrial wildlife specialist. “The data suggests that while the fire was devastating to red squirrel habitat and their overall population, this is truly a resilient species.

“Even though much work still must be done to help conserve and protect this squirrel to ensure its continued recovery, seeing this growth is extremely promising and a signal that our conservation efforts are working.” 

This annual red squirrel survey consisted of visiting all known middens, which are areas where red squirrels store or cache their cones. Activity at these middens is used to estimate the population size.

“The squirrels are teaching us about their resiliency and how they respond to altered and even devastated habitat,” said Jeff Humphrey, USFWS Arizona Ecological Services field supervisor. “The survey results are a ray of hope in our partnership efforts to address their post-fire habitat needs.” 

The subspecies was listed as endangered in 1987. Mount Graham red squirrels live only in the upper elevation conifer forests of the Pinaleño Mountains and feed primarily on conifer seeds. This subspecies is highly territorial and has lower reproductive rates than red squirrels in other locations.

“The Safford Ranger District is pleased to see an upward trend in numbers for the Mount Graham red squirrel. This is very encouraging as we move forward in working with our partners and community in ensuring the long-term health and resiliency of the squirrel,” said George Garcia, Safford District Ranger for the Coronado National Forest. “We work together to actively manage and restore forest conditions for the benefit of all the species on Mount Graham.”  

Long-term impacts to Mount Graham red squirrels and their habitat include high-intensity wildfires and associated insect infestations, possible competition with Abert’s squirrels and poor cone crops caused by drought, all of which influence population size. Biologists continue to explore new methods to conserve and protect  the species, including continued squirrel research, developing long-term forest management strategies across the fire-impacted landscape such as re-seeding and planting coniferous trees, and a managed care breeding program.