Kadira rushed in to her father's study, brown eyes wide as she grabbed his chair and looked up at him in earnest. "Papa! Papa! I need to know."
Kadira's father quirked a bushy brow as he looked down to his daughter. "What, child," he grunted, pulling her up into his lap. "What is it?"
"Papa." Kadira's brows furrowed deeply, her lips pursing in intense concentration. "Papa, where do babies come from?"
With a faint grin, Kadira's father looked up to the ceiling. "You should ask your mother."
"Mama told me to ask you!"
"Of course she did," he chuckled, leaning back in his seat and studying a distant book on the bookshelf. "Hmm, let's see, where shall I start then... babies..."
Kadira's face brightened and she settled down to listen.
"They are carried through the sky by a phoenix," he answered, "as a gift to a mother and father. Sometimes the gift is an answer to a prayer, sometimes it is a complete surprise. Sometimes they even bring more than one." With a smirk, he gently touched her nose. "Like you and your sister. When your papa heard the news, he passed right out... in gratitude, of course."
Kadira giggled. "You fainted, papa?"
The man huffed quietly, shaking his head. "It was a wonderful surprise. And each time the phoenix brings a baby, he gifts it with one of his feathers, and that is the spark that lights the soul. And when that feather finally fades, it burns away and reforms upon the phoenix it came from, to be gifted once more."
I used an archaeopteryx as inspiration for the type of bird this phoenix is modeled after, and thought that maybe different areas might have different folklore for how babies come about, beyond just "well a mommy and daddy sign a contract, and that's how babies are made!"