Hi Waldemar

> Most tree colonies I've worked with had a single entry hole.  Inside the hollow above the colony, there is typically a dead wood core of the tree.  In my opinion, this dry wood (without direct opening to the outside) acts like a sponge for the moisture generated by the wintering cluster.

I have no problem with that, but water being wicked away by timber 
fibres is not the same as a top vent which would allow gas to exit and 
promote actual airflow.

> I noticed some bees using a couple of holes perhaps 3/8" in diameter...
> Those extra holes were not propolised but the were located 6-10" above the top of the combs

I have seen holes and cracks in this position, but they were propolised 
shut.

I have also seen vents in the top of a full colony observation hive that 
were propolised, but the bees re opened the holes when they needed to, 
what I would like to know is... Once a hole has been sealed, how do they 
know where the hole is to unblock it ?

The pattern of propolising of OMF (screened bottom board) is similar to 
that you describe for above the colony, but only occurs very rarely in 
UK (1% or less) once the process has started it seems to gather 
momentum. It does occur if you leave a monitoring board in place, 
because a build up of wax moth dross occurs under the mesh and then the 
bees seal it up.

> do you get many/any feral colonies in trees or structure in the UK?

We get colonies in trees and church walls, but it would be difficult to 
describe them as feral, they are beekeeper escapees and die out (assumed 
due to varroa) then the same cavity is re occupied by a swarm and many 
casual observers would say that the site has been in continuous occupancy.


Regards & Best 73s, Dave Cushman, G8MZY
http://www.dave-cushman.net (http://website.lineone.net/~dave.cushman)
Short FallBack M/c, Build 7.01/2.01

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