Pessimism: The mood of pessimism is introduced by a description of the weather as spectre-grey, the sun as weak, the end of winter as dregs, and the stems as strings of broken musical instruments. In the second stanza the land is pictured as a corpse and described as shrunken.
Irony: I’m not sure that this poem is intended as ironic. I think the contrast between the thrush carolling, and singing of blessed hope and the agnostic narrator surrounded by misery is intended as serious. This is a typical contrast in Hardy’s poetry reflecting a nostalgia for a kind of country life and simple piety in which he can no longer participate due to his own intellectual sophistication.
Satire: The poem is not a satire..
Hardy's poem depicts an atmosphere of pessimism as he stands at the edge of a "coppice" facing a desolate landscape towards the end of winter. While "all of mankind" is comfortable together beside their household fires, the speaker is alone on the "haunted night." The bleak landscape is Hardy's depiction of the turn of the century, and he describes his pessimistic attitude by commenting "every spirit upon earth Seemed fervourless as I." Scenes of the "cloudy canopy" and the "death-lament" of the wind add to the depressing atmosphere. After hearing the joyful song of the "aged thrush," the speaker again depicts his pessimistic attitude because he cannot seem to understand why the bird is so hopeful.
The irony throughout the poem lies in the fact that the thrush is hopeful for no reason. The speaker realizes that there is no reason for the thrush to be joyful in the desolate environment and does not share the same feelings as the bird. The satirical nature of the poem concerns Hardy's pessimistic views of the 20th century. While many people had optimistic views of the future, Hardy sought to recapture a simpler time before industrialization.
In my opinion you can see irony from the beginning with the title " The Darkling Thrush". In choosing words, Hardy paid a great amount of attention to the words. He could use " The Singing Nightingale" instead of that tiltle but he didn't; and the point is that he wants to use this title to show the pessimistic atmosphere of the coming century.
Hardy wrote this poem on New Year Eve and you can find examples of pessimism from all parts of it that are foreshadowing the gloominess of the coming century. "His crypt the cloudy canopy" is an example of pessimism and irony for the loneliness and gloominess of the situation.