Heather,
Two ways (at least) to look at it. OK, above posts have covered the difficulties of putting numbers on it, but 1) if I were putting my hive(s) on a site I would want the minimum around, or near, to maximise my return - if I were just doing it for the honey. 2) At some stage there will be a point where maintenance of the colony(ies) is barely achieved - so no harvest available.
Other factors might be whether the owners of the colonies are going to remove all honey, and replace with all sugar, for a harvest; whether a permanently occupied site (some colonies moved temporarily to OSR/beans/etc.).
I nearly always move most to the forage at some point in the season. Those on OSR always have the honey nicked early (to avoid crystallisation) and might not get much more unless moved somewhere else.
That said, a couple of colonies in the garden (edge of town and within reach of a stretch of river bank) gets a fairly reasonable crop. A mile represents an area of some 800Ha which is equivalent to 100Ha per full colony. Seems a lot until you find there are another thirty sharing your patch, and some of the patch is down to mono-culture crops, and worse still arable, as in wheat, barley, etc.
I would think your out-apiary will always be questioned as to number of colonies, however few or many you have!! 'Cos if you found you would be better to move a couple of colonies who could you ask? Low yield will be blamed on colony density, regardless of state of colony etc. No win situation. But, like you said, time will tell.
Regards, RAB
