Three small moments from a garden and a country road, each one a little trick played on the eye. In the first, a chickadee gathers what looks like thistle down for its nest. Then the speaker looks again and realizes the soft material is his own white hair, left over from a haircut a month ago. It's a funny, tender discovery: the bird has found a use for something he'd thrown away, and his aging has become part of a nest.
The last stanza shifts the trick to nature itself. A spring azure butterfly lands on blue gravel and vanishes, probably because its color matches the road so well. The speaker doesn't explain this, and that restraint matters.
The mood is quiet, amused, and gently wondering. The speaker seems to accept growing older without fuss, even to find some pleasure in it. The title fits: the poem is about things appearing as something else, and about how much a patient observer can notice.