I think at least one set of bird-maidens is going to be of a bird that doesn't exist except as a species that maidens transform into. (If I track down the tale I half-remember, I may get the details from it.)
And then there's the jungle girl. The problem is that the first jungle birds that pop to mind are parrots, and your bird is determined by your character. A quiet and mild character like the maiden from the jungle would not turn into a parrot.
Ah, well, there will be canaries. Possibly involving a magic book. And a green bird that's a green knight in human form.
And who knows? They may increase in importance if the tale calls for a sequel.