I missed the descriptions. The nora (a demon) was only "bald-headed". Well, that's a lot, everyone can imagine her now. And the midwife (who were with them) she is just a midwife, no description needed, of course, we all know how this midwife look like. Okay, the Lidérc (another demon) got a proper description with flames, and goose-leg and horseleg-hand.
I assume the birds came from the same world as the humans (I know they mention other world), they just lost their humanity, and travelled out of time, at least when they didn't lost their memories.
Still there was a part I really liked. It was a dialogue that had the same rhytm and structure just like in the folk tales, when the Fair Lady told her minions what to do to perish every one of her enemy (to send a girl to the Raven and drink for the coachman etc..).
It was like when in the Little Red' tale, the girl asks the wolf - 'Grandma, why are your eyes soo big' - 'To see your better' - 'Why are your ears so pointy' - 'To hear your better' etc...