> Wouldn't it be better to try to eliminate the need for a top entrance rather
> then constructing "moisture catcher"? Put the effort in finding a bottom
> construction that is efficient enought.
>
> Are all beekeepers in the US and Canada using top entrance during winter?
> What is the reason for it when it's not needed here? The north of Sweden has
> as cold winters as Canada, and probably longer (lat 65).
 
The two main reasons for upper entrances IMHO are:
 
1.  To provide air if sleet or drifting plug the bottoms with hard
     snow or ice - or dead bees accumulate there. This former
     event  occasionally can result in mass suffocation of hives.
     This is a rare but costly event.
 
and
 
2. To ensure that the bees can fly from *double* brood chambers
    in the spring when it is a very long walk down to the bottom
     board from the cluster. (Here we are again with the differences
     between single and double broods).
 
I've noticed that since I've put auger holes in each upper box, that
the weaker colonies do not drift out to the stronger ones as much
after we unwrap in the spring.
 
Formerly, the bees from weak colonies were drawn to the entrance
activity of the stronger hives and would move in there on their first
flight.
 
I don't notice much difference between hives with a 1/8
square inch hole (1/4" X 1/4") and those with 3/4 square inch
(3/8" X 2") hole.
Regards
 
Allen
 
W. Allen Dick, Beekeeper                                         VE6CFK
RR#1, Swalwell, Alberta  Canada T0M 1Y0  Internet:[log in to unmask]
Honey. Bees, Art, & Futures <http://www.cuug.ab.ca:8001/~dicka>