Mount Graham red squirrel numbers rising, officials say
The population of Mount Graham red squirrels in Arizona has reached triple digits for the first time since a wildfire pushed the subspecies close to extinction three years ago, state wildlife officials said Monday.
But while the annual survey data shows that the population has more than tripled since the fire, from 35 to109, the squirrel is still critically endangered and its habitat remains at risk.
“The population has come back from large scale fire events in the past, so these numbers and the squirrel’s history gives us hope they will recover again,” said Melissa Merrick, an assistant research scientist for the University of Arizona’s Mount Graham Red Squirrel Monitoring Program.
“But there are still threats facing this animal that could lead to its extinction,”
she said, “the most significant being this megadrought we’re experiencing that stresses trees, thus jeopardizing the squirrels’ source of food and shelter.”
The squirrel, which lives only on Mount Graham in Arizona’s Sky islands, has been listed as endangered since the late 1980s. It is one of over 20 subspecies of the American red squirrel that is native to forests around the country.
In 2017, the survival of the Mount Graham red squirrel was dangerously in doubt after the Frye Fire nearly wiped out much of its preferred environment. The squirrel’s high-altitude habitat, east of Tucson, has been the crux of several lawsuits this year.
The results from the 2020 fall survey mark the first time the squirrel population has returned to triple digits since the lightning-caused Frye Fire, which burned roughly 48,000 acres, leaving food sources low.
“What we have left is so critical and the fact they are rebounding is encouraging,” said Holly Hicks, the small nongame mammal biologist for the Arizona Game and Fish Department. “We’ve got to make sure we maintain what we have now and keep improving the habitat for the squirrels in the future and that is going to take time.”
The rodent’s population is recorded by visiting known middens in the Pinaleño Mountains of southeastern Arizona. These middens are where the Mount Graham red squirrels cache their cones. The activity in these areas is what’s used to estimate population size.
The squirrels were thought to be extinct in the 1960s until they were rediscovered in the early 1970s. According to the game and fish department, the population peaked at around 550 in the late ’90s.
“The last few years have been tough because of how much critical habitat we’ve lost,” Hicks said. “So we’re inevitably going to hit a population threshold for these guys because it’s going to take decades for trees to regrow.”
Too many environmental variables are at play to make an accurate prediction for when that threshold might be reached, said Hicks, who coordinates endangered species recovery projects around the state.
The annual surveys will continue and Hicks said she’d “definitely be dancing” if the population grew to 150 next year.
The survey is conducted each year on the last full week of September by the game and fish department, Coronado National Forest, U.S. Fish and Wildlife Service, Arizona Center for Nature Conservation and the University of Arizona.
“Populations can change so quickly with all of these external variables, especially with climate change, that we’ve got to keep consistent tabs on our endangered species,” Hicks said. “Lots can happen in a year to both a species and a habitat that we need to be able to detect significant changes.”
The endangered squirrels live only in the upper elevation conifer forests of the Pinaleño Mountains, where conifer seeds and Douglas fir cones — the bulk of their diet — are abundant.
These forests have been the crux of several lawsuits this year that have been filed against federal agencies by local environmental groups trying to widen the protection of these areas.
In mid-September, the Center for Biological Diversity and the Maricopa Audubon Society filed a notice of intent to sue the U.S. Fish and Wildlife Service for failing to conduct a 12-month finding, a step to revise the squirrel’s existing critical habitat.
“There is very little habitat left for the squirrel because of wildfires and human structures. If we don’t give them a bigger habitat than they can’t survive long term,” said Robin Silver, one of the center’s co-founders. “Short term, we can have a population of 109, but that’s not a number that’ll support long-term survival. They need a bigger habitat for a bigger population.”
This suit, which will be filed later this month — 60 days after the notice of intent — follows a summer suit the center filed against federal agencies “for failure to adequately protect and conserve” the species and its habitat. The earlier suit said the federal government did not properly evaluate how human structures have caused the squirrel harm.
“While I’m gleeful the population isn’t in decline and actually in a small incline, there is still no new habitat,” Silver said. “The issue isn’t that we’ve got a small population, it’s that we haven’t protected any new habitat for it to grow.”
Anton L. Delgado is an environmental reporter for The Arizona Republic/ AZCentral. Follow his reporting on Twitter at @antonldelgado and tell him about stories at anton.delgado@arizo narepublic.com.
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