Whereabouts: singular or plural?

Hard though it may be to believe, Toronto's Bad Boy mayor Rob Ford is a constant inspiration to Wordlady. At least he keeps giving me ideas for posts. First there was the burning question, "How do you spell 'drunken stupor'?", then there was the question of just how "incontinent" he is, and finally, the interesting origins of the word "lewd". But Rob, with Wordlady as with so many things, keeps on keeping on.

Most recently the hot topic, since he abandoned his re-election campaign, purportedly to go into rehab, has been his whereabouts. So of course inquiring minds want to know: What's correct: "His whereabouts is unknown" or "His whereabouts are unknown"?

"Whereabouts" is an odd word, when you look at it. Most people probably think it's obvious that it's a plural noun; after all, it's got an s on the end. So clearly, "His whereabouts are unknown" is the only correct version. But in fact, that s isn't English's regular plural noun marker, it's actually an adverbial -s, left over from Anglo-Saxon. It turns up in other words, such as "always", and the much castigated "anyways", as well as "forwards" and the other -wards words.  So, when "whereabouts" was first used, in the 1400s, it was, like its cousins "thereabouts" and "hereabouts", an adverb: "Whereabouts art thou?" (which in fact meant "What are you up to?"). It was not until 300 years later that we started using it as a noun synonymous with "location". We haven't effected the same function shift with "thereabouts" and "hereabouts", interestingly.

For the first couple of hundred years after turning "whereabouts" into a noun, we treated it as either singular or plural, but by the 1970s, the force of that final -s exerted itself, and since then it is used much more frequently with a plural verb. Most dictionaries are somewhat weaselly on this point, saying something like "as sing. or pl.", which, though true, doesn't much help the user who wants to know which one to choose. The Canadian Oxford Dictionary (wonder who supervised the production of that useful tome!) at least has a usage note to the effect that the plural is more common but the singular is not incorrect. I would venture to predict that within another 100 years or less, it will be used only in the plural. 

You may still come across some usage commentators who insist it has to be singular, but you can ignore them.

And let us all hope that we will never be in a situation where we need to talk about Rob Ford's "hereabouts"!