Why speculate about disembodied Nazgul occluding the stars when a Nazgul on a Fell Beast is a better supposition?

[Flammifer]

Are we looking at this from the viewpoint of first-time readers or repeat readers? Because it seems the "first-time reader" argument is swiftly invoked to shut down any argument, yet conveniently ignores the fact that a first-time reader wouldn't have any reason to think fell beasts for Nazgul are a thing yet.

Hi JJ48, You are correct that to the first-time reader, the mysterious shadow passing over the stars is simply that - a mysterious shadow. The first-time reader has very little evidence on which to speculate. If asked to guess, the guesses might be 'a bird - one of those crebain? Maybe an Eagle?' or perhaps 'could it be a dragon?' (if the reader had read The Hobbit).

However, it was not this question which I was addressing from the perspective of the first-time reader, but the question of who's spies the crebain (and later the wargs) might be: Sauron's or Saruman's? Here all the previous passages on spies, and Gandalf's comments (shortly afterwards) have been mentioning 'spies of the Enemy', meaning Sauron. So, I think the first-time reader should assume that is who the spies (if spies they are) belong to.

Now, later on, there are passages which might cause us to wonder if they were not in fact spies of Saruman? I wonder who's spies JRRT imagined them to be? Or did he envisage them differently at different times?