> Now, if the > bees are using up the available oxygen, leaving carbon dioxide, which will > rise with the heat created, the hive becomes a death trap. The bees move > upwards during the winter eventually ending up against the inner cover, into > the strongest concentration of carbon dioxide. Cabcon dioxide is *very* significantly heavier than air. 02 is roughly 16 + 16 = 32 CO2 is roughly 14 + 16 + 16 = 46 (If I remember my chemistry correctly). Weighing roughly 150 % as much as air, it sinks like a stone. The hive has to be sealed pretty completely for it to be a problem. CO2 leaving the cluster soon cools and drops, then runs out the entrance like water. Nonetheless, it can be a problem under some circumstances. I seem to recall Shapiriw (sic?) doing some measurements some years ago in the development of his inner cover design. Many beekeepers have reported having wrapped or unwrapped hives covered over completely with snow and having better than usual success. Ice storms that completely glaze over the hive could be a problem though. I'm a bit more concerned about excessive air exchange - with consequent heat loss - than too little, but that is out here on the bald prairie where winds are high and humidity is low. Now, does anyone have a solution for mice - other than poison? 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>