Inside: Upper entrances have many advantages and a few drawbacks. Carefully consider the size and position of any above-the-brood-box entrance.
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Don’t get me wrong. I love upper entrances and use them a lot. EAS master beekeeper George Imirie was passionate about upper entrances and frequently wrote of their importance. He believed they solved two primary problems: they shortened the distance returning foragers had to travel through the hive and they provided hive ventilation, especially in winter.
Imirie was the eponymous designer of the Imirie shim, a 3/4-inch rectangular frame with the same footprint as a Langstroth box. In the center of one end, a 3/4-inch by 3/8-inch entrance is notched into the wood. Imirie used this frame between honey supers in the summer and above the brood boxes in winter. According to his writings, he designed the shim because he didn’t like drilling holes in his boxes.
Entrances can be drilled directly into boxes
If you don’t mind drilling holes in your boxes, a drilled hole eliminates the problem of burr comb between boxes. Imirie thought the burr comb was a small price to pay for the increased efficiency of the foragers, and he didn’t mind scraping it away.
Other beekeepers, like Tony Bees in New York, swear by holes drilled directly into the honey supers. He gets huge quantities of honey by using these upper entrances combined with little landing pads for the foragers’ convenience. I converted to this method and drilled one-inch holes in my honey supers which I then placed over a double-queen hive.
Top entrances aid pollen collection
In addition, I use a 3-inch shim (also known as an eke) with three one-inch holes drilled in the front on those hives where I plan to collect pollen. I like the Sundance II top-mounted trap, but it requires that the bees first be accustomed to an upper entrance. I use the 3-inch eke with the three holes to “train” the bees. When they are comfortable with the new entrance, I simply exchange the eke with the pollen trap.
When I’m ready to remove the trap, I switch the two again and the bees go right back to using the three holes. Seamless, as they say.
Alternatives for upper ventilation
Personally, I don’t rely on a single upper entrance for ventilation. For a very large and populous colony, it doesn’t seem like enough.
In my mind, ventilation and entrances are separate issues, and I prefer to use a screened inner cover for summer ventilation and a quilt box with screened ports for winter ventilation. Of course, the amount of ventilation required will vary dramatically with your climate and the size of your colony. Under some circumstances, a single small hole will be enough.
And now the gentle warning
I see a lot of beekeepers using two small blocks of wood inserted under the lid or under the inner cover to create a huge upper entrance. In fact, I was taught to do this, and at one time I had a box of these little wooden blocks ready to go.
The problem is little blocks make ginormous upper entrances. Even if your block is only 3/8 inches high, the entrance extends the entire width of the hive and partway back on both sides.
This configuration is no problem for a large and populous hive. But if robbing begins, a small colony can quickly be overrun by invaders coming through this large entrance. And remember, the colony must guard the bottom entrance at the same time. Of course, if the top entrance is your only entrance, the situation is not as bad. Still, size is an issue.
Robbing happens fast so prepare in advance
It is easy to forget that robbing happens fast. You can go to work one morning only to find all your honey stores gone by evening. It’s not just other honey bees, but yellowjackets, wasps, and hornets as well.
In fact, if you feed during a dearth, many sources recommend that you move the feed as far as possible from the entrance. This is so the scent of the feed is not strongest right where the opening is. So, for example, if the feed is at the top of the hive, the entrance should be at the bottom. This is another good reason to close up the top during a dearth.
The lesson is simple, if you elect to use a big gaping hole as an upper entrance, you’ve got to close it before robbing season begins. You can’t forget and you can’t be late. Trouble is, because it is often blistery hot during robbing season and because the entrance doubles as a ventilation port, the tendency is to wait too long. This is exactly why I like to treat entrances and ventilation as separate problems.
Avoiding the big-entrance problem
If you’ve drilled upper entrances in your honey supers, you don’t have this problem because your honey supers have normally been removed by robbing season. And some beekeepers, like Tony Bees, add hinged covers that can be closed.
If you use an Imirie shim for an upper entrance, it is probably defensible by all but the weakest colonies. Or if you use multiple holes in a 3-inch rim, you can easily plug the holes with wooden or plastic buttons or a piece of duct tape.
In any case, a small entrance, whether it is round or rectangular, is easier for the bees to defend than a long, continuous one. If you read Thomas Seeley’s book Honeybee Democracy you will see that swarms are very particular about the size of the entrance opening. Although honey bees will sometimes select a long and narrow opening in a tree, it is usually quite slender and there is normally just one. Although we can only assume their motivations, colony defense seems a likely factor in their decision-making.
Other considerations: pests and predators
Large top entrances, especially on small colonies, also invite other problems such as wax moths and ants. If the colony is not guarding the top entrance, pests have easy access to your combs. If you use a screened inner cover, or screened ventilation ports, you can exclude some pests, especially wax moths.
On the flip side, upper entrances are especially nice in winter because the bees can come and go without having to dig through a pile of dead bodies. And predators, especially the furry mammalian type, have a harder time catching bees as they come and go from a top entrance.
To sum it all up, I like upper entrances and think they provide many advantages. But those of us using multiple entrances, especially ones at both the top and the bottom of the hive, need to be aware of the disadvantages as well.
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