What tree-dwelling rodent has tufts of long hair on its ears, ranges in color from jet black to pale brown, and relies almost exclusively on Ponderosa pines for survival? If you guessed Abert’s (or tassel-eared) squirrel, you are correct. Restricted to open montane forests, the Abert’s squirrel can be seen in the winter foraging on the terminal twigs and phloem (inner bark) of the Ponderosa pine. They also dismantle pinecones to reach seeds and enjoy a pine bud or two every now and then.
Unlike some of Colorado’s other squirrels, the Abert’s does not establish winter caches of food. That’s good news for anyone seeking to observe this tree-dwelling rodent because they spend a great deal of time out in the open searching for food, especially during the colder months. To find out where Abert’s squirrels feed, look for evidence of chewed-off needle bundles, partially eaten cones and small, bark-stripped twigs on the forest floor below the trees.
Studies of Ponderosa pine forests along the Front Range revealed that squirrels feeding on trees can reduce cone production by as much as 74 percent. Fortunately, only about 10 percent of the trees within individual stands of Ponderosa pine seem to be targeted by the squirrels. These selected trees contained lower levels of chemicals called monoterpenes, while the majority of the trees containing higher amounts of chemical were not eaten. Thus, most of the pines have a natural defense against these bark-gnawing rodents.
If you are fortunate enough to visit a montane forest inhabited by Abert’s squirrels after a fresh blanket of snow has been laid down, look for the tracks and trails left near the base of trees.
Individual tracks can be identified by the classic 1-3-1 toe arrangement of squirrels and other rodents. On the front track, three toes are grouped together and oriented forward, while the two toes on either side are smaller and angled outward.
Squirrels often leave a bounding trail that shows the larger hind prints in front of the smaller front prints. Although the tassel-eared squirrels can be fairly quiet while foraging for food, they do have several vocalizations including alarm barks, tooth chattering, screams, and clucks. So listen, too!