I never saw a wild thing
sorry for itself.
A small bird will drop frozen dead from a bough
without ever having feit sorry for itself.

Lawrence conveys to the readers that a small bird does not live in chronic fear and worry, it rather moves on living life. Humans often have a tendency to be melancholic and broken-hearted due to events that do not go as they wished or instances that cause a misfortune. We can get inspiration from animals and learn to live life as it comes, instead of grieving on the misfortunes of the past.