There are a two chronological inconsistencies with Topal.
Here is a man who follows his orders explicitly, and knows that he should have been going south-east through river ways to reach Firsthold. Looking at his maps, we can see that he attempted to find passages through, as he has mapped out the Inner Sea of Morrowind, and several of the swampy tributaries of Black Marsh, no doubt being turned away by the disease and fierce Argonian tribes that dissuaded many other explorers after him. - http://www.imperial-library.info/obbooks/father_niben.shtml
For sixty-six days and nights, he sailed, over crashing
Waves of dire intent, past whirlpools, through
Mist that burned like fire, until he reached the
Mouth of a great bay and he landed on a
Sun-kissed meadow of gentle dells.
As he and his men rested, there came a fearsome howl,
And hideous orcs streamed forth from the murky
Glen, cannibal teeth clotted with gore - http://www.imperial-library.info/obbooks/father_niben.shtml
The poem suggests that in the Merethic, Topal sailed the Inner sea of Morrowind and observed Orcs in what is now High Rock. However, we know that the Orsimer weren't there yet at the time. They came much later, around the same time as the Velothi Exodus.
Dwemeri high priest Kagrenac then revealed that which he had built in the image of Vivec. It was a walking star, which burnt the armies of the Triune and destroyed the heartland of Veloth, creating the Inner Sea. - http://www.imperial-library.info/mwbooks/lessons.shtml
In my research of the very oldest Nord records, I found ancient maps which showed no island in the north of modern Morrowind -- just a region labeled "Dwemereth" which encompassed the island of Vvardenfell as we know it, as well as a rather wide swath of what is now the mainland. Indeed, as best as could be made out from the rather crude map, the coastline once extended some distance further north than Vvardenfell does now. - http://www.imperial-library.info/fsg/ghanburighanarticle1.shtml
For the origins of the Inner sea we have both Haspaht (Kurt Kulhman) and Vivecs Sermons to suggest that there was no Inner Sea in the Middle Merethic and that it was formed around the same time as the Battle on Red Mountain.
As such, I reckon that the original Poem of Father of the Niben doesn't actually come from the Merethic Era, but from a much later time period. It being a http://www.hbo.com/rome/ or a http://en.wikipedia.org/wiki/Gulliver%27s_Travels.
The alternative is that Nordic cartographers svck, Vivec was being poetic without reason and the Inner Sea was formed at the impact of a heavenly body and has been there ever since. Though this isn't quite as interesting as an Anumidium induced landscaping spree.
You're free to make up your mind about the origins or inspiration of the feathered folk. Perhaps they are a fiction. Perhaps there were feathered people who's customs were usurped by the High Elves as they moved in. If anything they didn't just wander into the authors mind, it's just that the Poem of Topal only goes so far as proof of their existence.
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Yes, Theodore. I try, but you don't make it easy.