The highly endangered Mount Graham red squirrel subspecies saw a slight population decrease over the last year, according to the annual interagency population survey.
However, squirrel numbers are still significantly higher than just two years ago due to improved survey methods.
The 2023 survey recorded 144 observed squirrels in the Pinaleño Mountains, down 12 from the 156 spotted in 2022 but up from only 109 squirrels counted in 2021.
“We saw a big increase last year because of our more thorough survey method, but it doesn’t remove the threats this squirrel still faces, and it will take time for them to recover,” said Holly Hicks, Arizona Game and Fish Department’s small mammal project coordinator.
Agencies Adjust Survey Technique, Gain Better Population Estimate
The Mount Graham red squirrel can only be found in the upper elevation conifer forests of Mount Graham located in southeast Arizona’s Sky Islands region. The Arizona Game and Fish Department, U.S. Fish and Wildlife Service and Coronado National Forest have collaborated for years to survey known squirrel middens, areas where the squirrels store conifer cones and other food. However, they realized this method failed to account for new middens established throughout the seasons.
After a three-year trial, the agencies now use a systematic plot survey technique. Surveyors designate specific plots to search instead of only returning to previously identified middens. This allows them to cover more terrain and detect new middens, likely contributing to the higher number of squirrels observed in 2022.
“The new survey protocol gives us a better idea of where the squirrels are locating their middens across the landscape,” said Benjamin Zack, Fish and Wildlife Service biologist. “It makes for more work to comb through broader areas instead of just checking known middens, but the payoff is a far better population estimate.”
Decades of Monitoring An Endangered Endemic Species
Thought extinct in the 1950s, a few Mount Graham red squirrels were rediscovered in the 1970s. In 1987, the squirrel was listed as endangered under the Endangered Species Act. In the 1990s, the population peaked at 550 before declining due to habitat loss from the 1996 Lookout Fire and development.
Another blow came in 2017 when the Frye Fire burned nearly 50,000 acres in Mount Graham, destroying much of the high elevation habitat. The squirrel count crashed from 252 in 2016 to just 35 individuals in 2017. Now six years later, the population is rebounding but remains endangered.
“These squirrels have nowhere else to go. They only exist here in the Pinaleño Mountains,” said Benjamin Zack, Fish and Wildlife Service biologist. “So we have to be extremely careful managing this fragile environment.”
The agencies plan to persist with conservation efforts through continued habitat restoration and public education. They also hope to maintain the improved survey methodology to better track squirrel numbers in years to come.