Lots of times I walk in the woods and don't see any animals. Sometimes I hear birds, but don't see them hidden in the leaves. Yet I always know they have been there, and sometimes I can tell how recently - or at least if it was recently or quite some time ago.
Here are some images of evidence of creatures besides myself and my dog.
a small tunnel entrance (mouse? vole?)
a clawed log (skunk?)
a stripped pine cone (red squirrel)
chewed acorns (chipmunk?)
tree holes (woodpecker)
I don't always, or even often, know who exactly has been there, but I love knowing that there is a whole web of lives going on around me, even if I can't see all the actors. It is thrilling to me to know the little that I do, and to be allowed in as far as I am.