Flying High: Scientists work to protect a flying squirrel and its red spruce home

IGC Fellow, Cordie Diggins, was recently featured in The Nature Conservancy Magazine. Author Madeline Bodin shares the recovery story of the West Virginia northern flying squirrel and the ongoing work to monitor the species and restore its red spruce home.

Flying Squirrel
Scientists measured, weighed and put a radio collar on this West Virginia northern flying squirrel before releasing it into the wild. © Patrick Cavan Brown for The Nature Conservancy.

Craig Stihler holds the squirming rodent in his gloved hands. “It’s a biter,” warns the bespectacled biologist as he handles the animal using only calm, deliberate movements. With its impossibly large eyes built for seeing in the dark, the West Virginia northern flying squirrel looks and acts like an agitated Muppet.

And rightfully so: A few minutes ago, this young female specimen was napping in one of hundreds of nest boxes that Stihler and other researchers installed throughout the Monongahela National Forest. But now she’s being weighed, ear-tagged and measured by a small group of scientists.

Cordie with traps
Virginia Tech doctoral student Corinne Diggins prepares live traps to capture and study West Virginia northern flying squirrels. © Patrick Cavan Brown for The Nature Conservancy

Virginia Tech doctoral student Corinne Diggins prepares live traps to capture and study West Virginia northern flying squirrels. © Patrick Cavan Brown for The Nature Conservancy

One of them—Virginia Tech doctoral student Corinne Diggins—blows in the squirrel’s face, trying to stop it from writhing in Stihler’s hand long enough for her to slip a radio collar around its neck. The animal finally holds still after a Forest Service technician gamely offers the finger of his glove for the squirrel to gnaw on, which allows Diggins to crimp the collar in place. Once she is done, Stihler releases the squirrel onto a tree trunk. It darts up into the canopy, then freezes in place, waiting for the group to leave.

A biologist with the West Virginia Division of Natural Resources, Stihler has held more West Virginia northern flying squirrels than just about anyone. He has been studying the animals since 1985, when this subspecies of the northern flying squirrel was listed as endangered under the federal Endangered Species Act. At the time, scientists could find the squirrel at only a handful of sites in West Virginia, and its only known habitat had been reduced to a small fraction of its historical footprint in the area. To make things worse, not much was known about the animal—including what it ate, where it slept and how it differed from its more common cousin, the northern flying squirrel, which ranges across North America. With so few of the feisty, nocturnal animals to study, figuring out why the squirrel had declined—let alone how to save it—was going to require some sleuthing.

Cordie Tagging
Researchers Corinne Diggins and Craig Stihler attach a radio collar to a West Virginia northern flying squirrel after measuring and weighing it. © Patrick Cavan Brown for The Nature Conservancy.

Only three decades later, the outlook for the flying squirrel’s survival has changed dramatically. The species is no longer endangered and was delisted in 2013—a remarkable feat, given how few squirrels remained and how little was known about them. The story of the squirrel’s turnaround isn’t about saving just one species; it’s the story of the restoration of an entire landscape that had become unbalanced by more than a century of logging and mining.

The West Virginia northern flying squirrel is a rare sight in the wild. Compared with the typical gray squirrel you might see in your yard, the flying squirrel is smaller, lighter, active at night and can soar through the air. It uses folds of skin, called patagia, that stretch between its front and hind legs to glide from tree to tree. It is so adept with these “wings” that it can execute 180-degree turns in midair.

Before the 1980s, scientists had observed this high-flying rodent scratching out a meager living eating tree buds, lichens and mushrooms. But it wasn’t until the subspecies was listed as endangered that researchers uncovered the mainstay of its diet: truffles—or a close approximation from the genus Elaphomyces. These truffle-like fungi grow below ground, entwined in the roots of trees commonly found in the high-elevation red spruce forests of central Appalachia’s Allegheny Mountains. Further investigation found that the trees, fungi and squirrels were mutually dependent: The fungi and the trees exchange nutrients, and the squirrels eat the fungi and spread their spores to new areas.

“You can’t underestimate the importance of the relationship between the forest, the fungi and the squirrel,” says Donna Mitchell, the West Virginia Department of Natural Resources biologist who conducted research on the subspecies’ diet—work that offered major clues toward understanding the animal’s decline. “I’m not sure what you would do without one of those components.”

Cordie with trap
Researcher Corinne Diggins sets traps in a variety of spruce and hardwood locations to account for the West Virginia northern flying squirrel’s foraging and denning habits. © Patrick Cavan Brown for The Nature Conservancy.

A second piece of the puzzle came into place when the U.S. Geological Survey published a report finding that the Allegheny Mountains’ spruce forests were among the most endangered ecosystems in the United States. The forests had been reduced to just 10 percent of their former range.

“This was a spruce-driven ecosystem, with a million acres of spruce-influenced forest,” says Shane Jones, a biologist with the Monongahela National Forest, looking out at a mountainous horizon that today shows only small patches of red spruce. “Then in the 1800s, mass timber extraction arrived with the railroad logging era.” Not only were the trees cut down, but sparks from the trains’ engines ignited fires in the hillsides, which were littered with slash from timber cutting. Having thin bark, a shallow root system and small seeds that burn easily, the red spruce is poorly adapted to fires. Eventually the hardwood trees, such as beech, maple and oak, grew back; the spruces didn’t.

For most of the past century, that situation suited the Forest Service. Maples, cherries and oaks were more valuable as timber. But as the flying squirrel mobilized local conservation groups—including The Nature Conservancy—during the 1980s and ’90s, they found that the red spruce forest held this ecosystem together. The trees shaded trout streams, provided habitat for an endangered salamander and supported the West Virginia northern flying squirrel.

The first step in restoring the squirrel population, then, was securing its remaining habitat: Logging was halted in areas of the national forest that could support the squirrels. The second was developing and implementing a restoration plan for the red spruce forest.

Since the early 1990s, the Conservancy has helped the Forest Service protect more than 65,800 acres of scattered parcels within national forest boundaries. The largest deal occurred in 2000, when the Conservancy coordinated the purchase of mineral rights for 57,300 acres on the flanks of Cheat Mountain, situated on the forest’s western edge. The Forest Service already owned the surface of the land, but a mining company owned the mineral rights, which meant it could tear up the forest to get to the coal. Once secured, the mineral rights were transferred to the Forest Service. … Finish reading this story at The Nature Conservancy Magazine!