Something someone said struck me as odd, when they spoke of the Wild Elves, transforming, birds, etc.
It made me think -
The elven armour and ayelid artifacts: They represent birds in almost every feature. Every piece of the armour set and weaponry set has a bird/eagle on it. Or, at least, that is what I see when I study the images/etc.
Of course I am by no means saying this is what the author of previous stated sources are referring to this. I am simply pondering - What if it was the "Wild Elves" or perhaps a more "ancient" version of them the author(s) saw, who, infact, could transform into birds.'' (Since it seems people are questioning the location of the W.E. during those specific times of the author.)
It just seems odd to me the Wild Elves themselves, and Elves, as well, have so many items and etc which resemble and reflect an eagle. (I think I remember reading somewhere the elven armour in OB is created/modeled after the Wild Elves')
BTW, after reading all of this, do please make a note that I am extremely tired and cannot form complete thoughts. So, wait, I just did, didn't I? Ah, anyways... Forgive my ignorance and lack of coherence.
http://www.imperial-library.info/fsg/prowelerarticle3.shtml. The article was linked to in the very first answer of the thread. In short, the bird symbolise (the ascension to) Aetherius, and thus, the gods - Auriel in particular. That is what the armour/weaponry/art represents.
And by the way, Wild Elves does not equal Ayleid, even though they "technically" are Ayleid. The people who built the ruins, and ruled Cyrodiil, were Heartland High Elf-Ayleid, not Wild Elf-Ayleid. Wild elves are the remains of that civilization - as was sated earlier in the thread, "Ayleid gone feral".
"Ancient" Wild Elves would therefore be Heartland High Elves.
Of course, what is interesting with the "birdmen" is the connections you can make to later, Ayleid, symbolism. If we combine the elven belief that they come from the gods, and the bird symbolism, with the fact that the islands are described more or less Paradisial in the text, you can easily find some intriguing results. A bit far fetched, however, since we doesn't really have any other, more reliable, sources.
And then there's the thing about the "birdmen" being described as stereotyped "natives", "uncivilized", and so forth - less "intelligent" than the Elves, if you wish. It doesn't go well with the "missing link to the gods"-stuff.
edit: I completely forgot where I was going with that stuff while writing, it seems. Aah well, too late now..