What song is played on the bugle when music is not available for evening colors?

The song played on the bugle when music is not available for evening colors is Retreat. This signal marks the end of the duty day and is traditionally played to call soldiers to return to their posts and prepare for evening colors. It serves as a reminder to honor the flag as it is lowered, reflecting the military's commitment to respect and tradition.

While Reveille is associated with waking and starting the day, the National Anthem represents national pride and is typically used during times of significance such as morning colors. Taps, on the other hand, is a somber song played at military funerals or memorials, signifying closure rather than the end of the day. Retreat distinctly fits the context of signaling the evening's conclusion and is recognized specifically for this purpose within military customs.