I hope I won't be accused of taking a side in this matter, for simply asking 
questions and testing the answers, or unread for assuming that *any* 
hypothesis is open to discussion.

>> After all, when a swarm moves through the air, almost all bees are flying 
>> pretty much in circles, being led as a whole by bees that have flown 
>> repeatedly to the target site.
>
> That does not explain the behaviour of a swarm during the time when it is 
> clustered and scouts are looking for the new nest site.  We can watch 
> dancing scouts trying to recruit for different sites and then gradually 
> coming to a consensus with many bees dancing for the same site (to which 
> the swarm moves - and which we can predict).

Let's divide that into two parts:

1.) what we see (the observation),

and

2.) what we think we are seeing (the interpretation).

First, we are seeing bees moving around in specific directions, speeds, 
frequencies, etc. ("the behaviour of a swarm during the time when it is 
clustered and scouts are looking for the new nest site.  We can watch 
dancing scouts..").  AFAIK nobody disputes this, and we have all seen it. 
The various movements (called -- somewhat anthropomorphically, "dancing") 
have been analysed and documented, perhaps completely, perhaps not, and we 
seem to be able to predict, sometimes with great accuracy, when the swarm 
will leave and also when we can expect it to go.  I understand, however that 
the accuracy of these predictions is not necessarily 100%.  After all, 
swarms sometimes stay on the congregation point near the hive, sometimes 
return to the origin, and sometimes go to locations other than the one that 
seemed to be indicated.  (Someone please comment).

Second, we *think* that the bees are able to read the same information that 
is so obvious to even a slightly trained human.  We have deduced this by 
conducting various ingenious tests and applying logic, and even using 
"common sense". This is much harder to prove conclusively, and while many 
proofs have been attempted, some tests have been found to be flawed in 
various ways, and others open to alternate interpretations. What many may 
consider proof absolute, others may consider to be merely persuasive, but 
incomplete or, possibly, flawed tests.

Some people are easy to convince, while others demand a higher standard of 
proof or multiple proofs, and question them thoroughly.  Some may never be 
convinced no matter how much proof is provided.  That's just the way people 
are, and as they say, "It takes all kinds".  Be that as it may, each serves 
a purpose, it seems to me, and we all have to get along.  Personally, when I 
ride a commercial jet, I like to think that there are some hard-to-distract, 
hard-to-convince, extra-careful, take-nothing-on-faith people in maintenance 
and navigation.

> All this can happen in quite strong winds which would remove any odour 
> trails immediately - or even light winds which would, presumably, send 
> bees off in the wrong direction and cause chaos!  The wind can be at 
> right-angles to the direction of the chosen new nest site.

Winds can definitely be a confounding issue for those who doubt or reject 
the language hypothesis, however the wind problem is not insurmountable 
inasmuch as the bees often mill around in large circles, flying through the 
general mass of the swarm in flight, so we can assume (there is that word 
again) that those who know may be able to somehow guide the group that way. 
(See opening quote).

As a slight broadening of the topic, let me ask how relatives of the bees, 
ants, wasps and hornets find a picnic, and how they recruit their nestmates 
so quickly

Again, let me reiterate, for those who skim rather than read pensively, that 
I have no position in this matter and an almost entirely open mind.  I enjoy 
the idea that bees might have a language and take pleasure in watching a 
swarm getting ready to fly and thinking I can understand what is happening, 
however I am aware that my senses and knowledge are very limited. 

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