For nearly ten years, I have not put upper entrances in my winter hives. My primary concern for winter was ventilation, but since I began using ventilated quilts on the top and screens on the bottom, I haven’t had any moisture or ventilation problems at all. My hives stayed dry and upper entrances seemed like just an invite for unwanted creatures.
But this year I decided to add candy boards that are designed to go beneath the moisture quilts. For some reason I can’t explain, I decided to put an Imirie shim with a small entrance below the candy boards. This small change has transformed my hives.
How? For all those years, I hardly ever saw my bees in winter. I would see evidence of them, of course—dead carcasses on the landing board, splats of bee poop on the lids during a warm spell, and the ever-present hum of the hive. But since I added the upper entrances, I see bees every day, bees crammed together side-by-side looking out on the world. They remind me of children huddled at the window, wondering why they can’t go outside and play.
Just a few minutes ago, I ran outside and took a few photos. Believe me, it is not bee weather out there—it is dark, rainy, windy, and 40 mildew-laden Fahrenheit degrees.
When I asked myself, why do they gather at the top entrance and not the bottom entrance, the reason became immediately clear: the top entrance is warm while the bottom entrance is cold.
Up is where the warm is
Just think about it. Cold air comes in through the bottom of the hive—through the lower entrance and through the screened bottoms, if you have them. This cold air is warmed to some extent by the bees’ bodies and respiration. As it warms it rises because warm air is lighter than cold air. By the time it gets to the top of the hive, it is much warmer than when it entered.
Remember my posts about temperature in the hive? The warmest place is just above the cluster. It just so happens that the little Imirie entrances are just above and a little outside of the winter cluster. Air exiting the hive at that point is probably downright balmy compared to the air coming in the bottom entrance.
Most likely, other reasons come into play as well. Since the winter cluster tends to travel up toward the honey supply, the bees in winter have a natural tendency to move in that direction. Then too, as the season progresses, the cluster is closer to the upper entrance than to the lower one.
Regardless of the reason, it is entertaining to have a little window on the bees. I love to see them. Who knows, maybe they find me amusing as well.
Honey Bee Suite