An adorable gray and white squirrel with distinct ear tufts has become the wildlife mascot of the Ponderosa pine forests above Dolores.
Hikers and bikers in the Boggy Draw area are more and more accompanied by the lively Abert’s squirrel as they scatter up and down trees and sometimes bound along the trail in front of cyclists.
“They seem to have become accustomed to the mountain bike traffic up there,” says Ivan Messinger, a wildlife biologist with the Dolores District of the San Juan National Forest.
An ongoing 10-year study of the Abert’s squirrel has revealed its population is increasing forestwide.
“The trend analysis shows a 7 percent increase every year between 2005 and 2015,” said Mary Hammer, lead wildlife biologist for the San Juan Forest.
The Abert’s squirrel thrives in Ponderosa forests and is considered an indicator species of forest health. Their upward trend shows that overall, the Ponderosa forest is healthy in southwest Colorado, Messinger said.
“Aberts are selected to monitor Ponderosa pine. It is their optimal habitat, and they are abundant because of the availability of food, cover and water,” he said.
Survey plots throughout the forest count animals and are recording more of the telltale signs of squirrel life.
Common sign are remnants of dissected pine cones, their favorite food, along with girdled branches they chew to get to the sap. Their tangled nests of branches and pine bows can bee seen high in the trees.
The Abert’s squirrel also eats acorns from the Gambel oak, and dine on various mushrooms as well.
“They are known to hang the mushrooms on trees,” Hammer said, perhaps to dry them out.
The squirrels have a symbiotic relationship with Ponderosa, Messinger added. They eat a fungi that grows on the tree, releasing spores that open up the soil and improve water uptake for the tree.
They don’t hibernate and can be seen year-round. They have various calls, including chattering and a distinct whistle. They are may be heard more often than seen, Messinger said.
“Like most squirrels, they are kind of uptight,” he said, and usually quickly flee humans.
The Abert’s is mostly preyed on from the air by raptors, including red-tail hawks, goshawks and Cooper’s hawks. They are occasionally caught by a lucky bobcat.
Why their population is steadily increasing is hard to determine, Messinger said. One probable reason is that there is less squirrel hunting than in the past. Or it could be their main predators have found an easier animal to target.
Catastrophic wildfire are their main habitat threat, he said. Recent thinning efforts in the San Juan National Forest has improved Abert’s squirrel habitat and reduced that risk.
“Give credit to the foresters for their fuel mitigation work on the Glade and Haycamp,” Messinger said. “Prescribed burns reduce litter build up and releases nitrogen into the soil that Ponderosas uptake. That contributes to good cone production which benefit Aberts.”