This poem has haunted me since I was 13 years old. As a cat lover (and a bird lover) I identified with the poet, the cat and the birds all at once. Beautiful work.
My cats have bells on their collars - very few successful bird hunts!
This is a perfect poem. We see the cat as flatly unsympathetic: even her owners lock her out and drown her kittens. But she's more than that: she kills thrushes and nightingales (and blackbirds, which are as colorful as crows and ravens aren't) and other creatures that we, as audience, prefer. But the larger forces of life (nature and 'God, ' whatever he, she, or it is) treat her more kindly. The poem is so understated that the last line is arresting and very tender.
This is a poem of welcome good fortune: to live a long life, being what she was meant to be despite all and then called home to rest by none other than God! Outdoor cats are in a war zone; pity Edward Thomas did not have the same good fortune.