How does the poem reveal that …

This poem tells that even a simple movement has a large significance. The poet has mentioned crow and hemlock tree in this poem. Crow signifies his depressive and sorrow full mood and hemlock tree is a poisonous tree. Both these signify that the poet was not in a good mood and so he describes the dark ,depressive and bitter side of nature to present is similar mood.
The poet says that once he was in a sad, depressive mood and was sitting under hemlock tree. A crow, sitting on the same tree shook off the dust of Snow i.e, small particles of snow that remain on the surface after the snow fall ,on the poet. This simple action change the poet's mood. He realised that he had just wasted a part of his day repenting and being lost in sorrow. But the change in his mood made him realise that he should utilise the rest of the day in some useful activity. His sorrow was washed away by the light shower of the snow dust. His spirit was revived and he got ready to utilise the rest of the day.