Nothing like an eye-catching subject to get people reading, is there?

Chris Slade, 25th January is really asking about a phenomenon known to sound
engineers as the cocktail party effect.  This refers to the ability of the
human brain, in a room full of talking people, to pick out and listen to one
particular conversation, not necessarily the loudest.

To apply this to the sounds in a hive, I think he would need at least a
stethoscope  to blot out the ambient noises of the countryside.  Even then,
I doubt whether he would hear the warble soon enough to be useful in
predicting a swarm.   Remember that the apidictor amplified the warble and
blotted out everything else. Still, anything is worth trying.

I'm a bit more optimistic about the thump and the hiss; I'm sure I have
heard this with the naked ear.  However, you do have to distinguish between
the two types of hiss.  One is an immediate response from an alert guard, a
sharp angry rise and ending quickly. "Push off", it says.    On the other
hand, if a swarm is in the offing, they are full of honey, half drunk, half
asleep and their hisses are slurred.   A bit slower to respond and not so
loud, they are saying, "We don't care, we're leaving soon, anyway."  When
you hear this, you had better get searching through the brood box.

I don't think it would be possible to depend on the hiss alone for swarm
prediction because it dies away when queen cells are started.  If you
have,'Listen to the Bees', there is a sketch on page 10, drawn by Eddie
Woods himself, showing the timing of these sounds.

Rex Boys.