Final answer:
The reference to keeping socks in a birdcage is a metaphor for unnecessary confinement, often relating to themes of freedom and restriction in literature, such as in Mary E. Wilkins Freeman's 'A New England Nun'.
Step-by-step explanation:
The reference to keeping socks in a birdcage and feeding them is a metaphorical way to highlight the absurdity of restraining things that naturally require freedom and do not belong in confinement. Much like birds, socks are not meant to be caged, signifying that they have no reason to be kept this way. Similarly, in literature, the imagery of caging birds often alludes to the restriction of freedom and may reflect on the characters or themes within the story. For example, in A New England Nun by Mary E. Wilkins Freeman, the confinement or restraint of the bird and the dog amplifies the overall theme of the story, representing the suppression of the central characters who crave freedom from societal expectations.