TUCSON, Ariz.— The Center for Biological Diversity and Maricopa Audubon notified the U.S. Fish and Wildlife Service today of their intent to sue the agency for its delay in protecting habitat essential to the survival and recovery of southeast Arizona’s highly endangered Mount Graham red squirrels.

“The Fish and Wildlife Service’s continued delay in providing Mount Graham red squirrels the protected habitat they need to survive is a recipe for extinction,” said Brian Segee, endangered species program legal director at the Center for Biological Diversity. “Since the squirrels’ existing protected habitat has been decimated by telescope construction and fires, accurate and up-to-date critical habitat designation is essential.”

Mount Graham red squirrels live only in the Pinaleño Mountains, an isolated “sky island” range in southeastern Arizona. Nearly all the squirrels now live outside the currently designated critical habitat areas, which include only spruce-fir forests above 9,200 feet, which is their preferred habitat. The squirrels’ original critical habitat has been destroyed by construction of mountaintop telescopes, wildfires and fires set unnecessarily to protect the telescopes. A 2022 census found that only about 150 squirrels remain on Earth.

In December 2017 the Center and Maricopa Audubon petitioned the Service to update the squirrel’s critical habitat to include lower-elevation, mixed-conifer forests. Those forest areas were not included in the original 1990 critical habitat designation since, at that time, most squirrels lived in spruce-fir forests at the mountain’s highest elevations.

In 2021 the Service said it would review revisions to the squirrel’s critical habitat after a species status assessment and revised recovery plan were completed. This followed lawsuits from the Center and Maricopa Audubon in 2019 and 2022.

Two years later the Service has yet to complete either of these tasks. Today’s notice says this ongoing failure to update the squirrel’s critical habitat designation violates federal law.

“The Mount Graham red squirrel is more imperiled than ever, isolated in pockets of canopied forest,” said Charles Babbitt, conservation chair at Maricopa Audubon. “The Fish and Wildlife Service has been fighting against moving recreational structures occupying the only short-term recoverable squirrel habitat by claiming the structures are outside of critical habitat. This cynical argument harms these rare squirrels and the region’s biodiversity.”