Today, Mr. Hancock sent an update on this fine little nugget. Thanks to Google Books, he uncovered a fuller explanation of what Hamlet is talking about.
"Harnsa" (phonetic spelling) was East Anglian slang for a heron. When a hawk chases a "harnsa," the heron often flies with the wind to escape its predator. When the wind is from the south, the sun is at the hunter's back, so he can easily differentiate between his bird and his bird's prey. (By contrast, when the wind is from the north, the hunter might have to squint into the sun -- and would have a harder time telling the difference between the two birds.)
What the commentator (from H.H. Furness's 1877 edition of Hamlet) doesn't say, however, is that the gloss only holds if the author of Hamlet's line knows East Anglian regional dialect -- and, presumably, has some experience hawking in that part of the country. De Vere, yes. Will of Stratford? Another misfit.
In Mr. Hancock's words:
Basically the important point is that a heron or hernsew is pronounced "harnsa" in Norfolk and Suffolk, which together constitute East Anglia. East Anglia is only about 150 miles from Stratford on Avon, but even in 2011 it is culturally and linguistically in a different country. ... It was presumably the same in the 16th century.
The Earl of Oxford was of course brought up in Suffolk, so he would have understood. It is very unlikely Stratford Shakespeare would have been familiar with Suffolk dialect, or would have [understood] written references to it.
It is pleasing to me that the reference to a handsaw had been correctly identified as being a "harnsa" or heron before 1877 by a Fellow of Trinity Hall Cambridge, and as such gives a little more academic credibility to the theory.
His original email to the SBAN Bulletin is below, after the jump.