A rather common but seldom seen denizen of our forests is the northern flying squirrel (Glaucomys sabrinus). They are strictly nocturnal and rather small (about the size of our more familiar red squirrel).

Jays are perhaps the songbird most familiar to Juneau resident. They are known by their bright blue plumage, with black head and crest.

The outer bark of trees evolved chiefly to protect the trees from pathogenic microbes, fungi, and some insects, and it may provide some incidental protection from damaging forces such as ice or falling branches. It is structurally and chemically resistant to damage and invasion, a set of adaptations that take different forms in different species. We observe some of the external differences along our trails — the ridged bark of hemlock, the scaly bark of spruces, and so on.