The speaker is an old man looking back at his own ageing. It starts with something small: grey hair at the temples, which he once found distinguished, even attractive. Over the years it spreads across his head, face and chest, and now it appears on his forearm. Alongside it come duller eyes, weaker limbs and a body that is slowing down.
The poem then settles into an evening scene. He sits in his armchair with a glass of whisky, watching the light slant and the shadows lengthen. These are quiet images of a day, and a life, drawing to a close.
In the last stanza, death is pictured as a visitor who will arrive silently on the wings of a Great Horned Owl. The mood is calm and resigned rather than panicked. The speaker sounds wistful and a little wry, and he seems to wait for the end with acceptance, even a gentle sense of ease.