.... likely because of some significantly different winter conditions and how the hive is prepared to endure those conditions.
Also, while people tend to call it an upper entrance; I prefer to look at it as the main purpose that is needed most of all, a vent.
In my climate, insulating the hive is a must, which seals off cracks and crevices from drafts entering the hive. Once wrapped, without the vent the bees are dead in short time. Because they are clustered so tight in the cold, there is no air movement. To be frank, they asphyxiate in the stale air around them as well as the build up of moisture chills and kills them. A small upper entrance/vent provides for passive ventilation to keep them dry and getting fresh air.
I am really curious, In Germany: What is your typical winter? When is the first snow that stays on the ground, what at the overnight lows and daytime highs typical of January/February, when does winter break and warmings of spring occur?
Hi there,
it`s a bit to be differentiated, though not as strongly as in the US:
Down south, Rhine Valley: wet winters, rarely snow, can get cold nights to -10 C. Mostly I guess it would hover around 0 C nights. And days just above. They live in perpetual fog down there in the winter...
Black Forest, just an hours drive into the hills: On higher grounds (1000 m above) snow may last till April, sometimes May. Not a must, though. I live at 500 m. It becomes green only beginning of May. In the Rhine-Valley Apple-Trees will be in full bloom or over then. We have had a hot and dry summer. Now it`s still prett warm, but where I live, a chill is in the air already. It?s 6 pm and 15 C. Nights are still about 10 C, though they are usually colder now. Daytime high was 19 in the shade. October usually brings first frost, November first snow, can stay on the ground then already. Some years it will be without frost till Christmas. But it has been heard of that snow came end of September and lay there till April. Hard frost and winter is mostly Jan/Feb. Usually the last winters are some spells of snow-fall. From 0 cm in the Rhine-Valley to over 1 m and more around our place. I got a snow-thrower. Usually it gets a bit milder in between with rainfalls (just above freezing), so the snow tends to melt away 3 or 4 times a winter and then fall again. When the weather is from the east (continent) it gets to freezing all day. "cold" is considered under -10 C. Some rare nights it will be -20C. But not every winter. "cold" I?d say -5 during the day and -15 nights. Higher up it gets colder.
In western Germany, more northerly, it`s usually milder from the Atlantic. Not much snow, wet.
In eastern Germany the climate is continental. October or November brings winter suddenly with frost and very little snow. Night-temps get around -20 and sometimes below there. Days are pretty darn cold then, too.
The alps are a bit different again... lots of snow.
Where I winter the bees, it`s almost as mild as in the Rhine-Valley. They have wine-yards there. First flow will usually be beginning of April. In the black forest: End of May. End of last flows most places: Mid-July (this year beginning of July). Black Forest: Pine`s still going.... but not to be harvested, rather to be avoided. Will load the last batch of bees tonight and haul them off.
There are beekeepers in Scandinavia. Winters are longer there. never heard of upper entrances there, but I am not into that. Maybe some reader from there among us? Please say!