TUCSON, Ariz.— Conservation groups sued the Trump administration Wednesday to force two federal agencies to comply with the Endangered Species Act and protect the imperiled Mount Graham red squirrel in southeastern Arizona from extinction.

The lawsuit, filed in U.S. District Court in Tucson, says the U.S. Forest Service and U.S. Fish and Wildlife Service have failed to evaluate how summer homes and an abandoned camp in the Pinaleño Mountains have harmed the endangered squirrels and their best remaining habitat. Earlier agreements with the agencies required those homes and structures to be removed.

“Federal agencies have abdicated their responsibility, and now these tiny squirrels are teetering on the brink of extinction,” said Robin Silver, a cofounder of the Center. “We’re hopeful that a judge will force them to do their jobs and ensure that red squirrels thrive again on Mount Graham. We’re in the midst of a massive extinction crisis that’s tipping the balance of nature, and we can’t afford to lose one more species.”

Mount Graham red squirrels live only in the isolated “sky island” range in the Coronado National Forest and feed on conifer seeds. Only about 75 remain on Earth.

The squirrels’ designated critical habitat includes only spruce-fir forests above 9,200 feet. Telescope construction, wildfires and fires set unnecessarily to protect the telescopes have pushed the squirrels to lower elevations and mixed-conifer forests that lack official habitat designation. Hotter, drier conditions from climate change are also believed to be harming the squirrels.

“For decades these rare squirrels have been chased from their homes by fire, construction and more fire,” said Mark Larson, Maricopa Audubon president. “It’s long past time for the agencies that are paid to protect endangered animals step up and safeguard the last places they live.”

“The recreational cabins and camp occupy the only canopied forest available for short term recoverable essential habitat,” said Roger Featherstone of the Mount Graham Coalition. “To save the Mount Graham red squirrel the cabins and camp must be removed as promised.”

Today’s lawsuit says the Forest Service should be prohibited from reauthorizing use permits for summer homes and the camp, begin a formal study of the potential harm to the squirrels from these uses, and develop a conservation program that includes removing structures and reforestation.

In response to an April 2019 lawsuit from the Center and Maricopa Audubon, the Fish and Wildlife Service last year agreed that designating additional critical habitat for the Mount Graham red squirrel may be warranted.