An eloquent response as always. I'm not looking to get into a debate on our differences of opinions either. Some believe excess ventilation is required and are successful beekeepers. Some believe differently and are equally as successful. My concern/objection, is the almost immediate write off of winter failure to moisture/lack of ventilation. This post is the perfect example, the gentleman admits his bees where weak all year and yet folks immediately suggested moisture as the issue. The gentleman even states he did not see any condensation on the inner cover when he checked them a few weeks ago.
It just is mind boggling to me that folks can't look past ventilation as the cause and consider queen failure. We are seeing package bees supercedure in epidemic proportions and commercial queens not even lasting an entire season. All the ventilation in the world ain't going to save a weak or failing colony.
An upper entrance is not required, an upper vent is. An upper entrance provides an entrance and a vent, look at it as economy of use.
Most of my hives have zero upper ventilation and are doing fine, while I have heard reports of others in my area already claiming 75-80% loss. I do consider it an economy of use. My well insulated hives help the bees retain heat and they use ~25-30% stores compared to my other hives. The retained heat also allows them to build up quicker in the spring. I can't imagine anyone debating the fact that warmth allows the bees to cover more brood.
In a regular beehive bearding develops quite often during the late spring and throughout the summer. Bees beard as much to provide ventilation as it is to cool the hive due to crowding. If bees near the entrance are watched closely it should soon dawn on an observer that some of the bees aligned along the entrance portion of the bottom board are fanning their wings to push air into the hive and another part are fanning their wings to pull air out of the hive, they are airconditioning the hive. Inside bees are fanning air up one side and down the other in an effort to keep the hive from overheating.
Forage bees returning to the hive land on top of the fanning bees, and enter the hive, forage bees leaving the hive climb up the box a ways and then take off. Meanwhile the bees aligned along the entrance of the hive (Often referred to as washboarding) continue pushing air in and pulling air out, circulating the air to vent the hive.
Around here, air conditioning refers to more than just moving air, but also removing humidity from the air you are displacing with. The general consensus seems to be that the more air that moves through the hive, the easier it is for the nectar to ripen. Yet Ed Clarke in "Constructive Beekeeping" does the math to show that if the bees had to rely of ventilation only, you would see fog coming out of the entrance and they would need a ridiculous amount of air exchanges per hour. His hypothesis is that they rely much more on condensation than evaporation.
The beekeeper in placing an upper entrance/vent (hopefully leaving the lower entrance operational) makes the work of the bees doing the airconditioning less strenuous on the bees as they only have to move the air in two directions, in and up, they no longer have to move it sideways, down and out.
I don't want to get into the beekeeper's will verses the bee's will again, but I still can't overlook the fact that when given a choice, it seems that bees prefer a closed cavity over an open one. Why would that be if ventilation is so critical to them?