This question is based on Literary Appreciation The sunset steals our youth We must depart We must follow the trail of the killer-bird Or else sleep the sle...

The excerpt portrays the theme of mortality. Every image in these lines points toward the inevitability of death and the passage of human life.

• "The sunset steals our youth" - sunset is a metaphor for the end of life, and the "stealing" of youth suggests the irreversible process of ageing and the approach of death.
• "We must depart" - departure here signifies leaving life, an acknowledgement that death is unavoidable.
• "We must follow the trail of the killer-bird" - the "killer-bird" is a symbol of death itself, and following its trail means all humans must eventually face death.
• "Or else sleep the sleep of terror" - "sleep" is a common euphemism for death, and the "terror" attached to it conveys the fear and dread that mortality can inspire.

While the excerpt uses imagery drawn from nature (sunset, bird), the theme is not about nature itself but about human mortality. The poem uses natural imagery as a vehicle to communicate the inescapable reality of death.