The section from the poem "The Caged Birds" illustrates the condition of the bird which has no control over its fate. It is explicitly captured within a prison and metaphors like "clipped wings" and "tied feet" propose that even if it tried, it is bound not to leave the premise it is contained in.
Further, in "Sonnet 29", the writer's allegorical language and expression portray the image of the narrator in the society where he feels unwanted. However, in the provided lines of the sonnet, the speaker laments on his position as an outcast and failure, also suggesting that this fate cannot be suppressed. Again, here, the condition of the narrator cannot be changed, same as the bird's situation.
Therefore, the common connotation suggested by the two excerpts is: "they both are angry at their circumstances," because they are stuck within their unfortunate conditions.
