[Peter Chipman]

In the original it's a "hrefn blaca"--a "shining (black?) raven," not merely a "shining (black?) bird."

One might argue that "hrefn" represents an emendation of the original word, except for the fact that the second half of the line speaks of "heofones wynne" (heaven's joy), and the mandatory alliteration between the two hemistichs requires the "h" of "hrefn," to match the "h" of "heofones."

So though your hypothesis is intriguing, Janice, the evidence of the text itself seems to be against it.

yours,
Peter