Answer:
My first is a creature whose breeding is unclear. My second, a price you must pay. My whole can be found in the river of Time and refers to events of today.
It comes only before, it comes only after. Rises only in darkness, but rises only in light. It is always the same, but is yet always different.
Whiling away the hours of flowers, Walking through fields of gold. Preening and pruning in lights fading hours, For petals to freeze in the cold. What is it?
I sleep by day, I fly by night. I have no feathers to aid my flight.
What can be swallowed, But can also swallow you?
What is full of holes but still holds water?