Some are the innocent victims of the necromancer's, some are her deluded accomplices who ended up victims, some, perhaps, are unrelated to her but still hanging around for reasons TBD (by the plot of course, not me 0:).
There are also some beneficent birds. Not talking, that would be too easy, but definitely beneficent.
And I'm playing around with some things I was using for inspiration, and noted I had put in some malignant birds, too. . . .
Are all the birds ghosts, too? (I toyed with the ideas of butterflies, but no, birds it is.)
The adventures of world-building in the earliest stages.