An entrance reducer is simply a barrier placed at the entrance to a beehive that reduces the size of the opening. They are usually made of wood, but can also be made from metal or plastic.
Many entrance reducers—especially the wooden ones—give you a choice of two entrance sizes. Others have just one size. Some of the metal and plastic ones are continuous.
There are many reasons to use an entrance reducer, although they are almost never used at the height of a nectar flow.
- Entrance reducers may be used to protect a weak hive from invasion by robbing honey bees or yellow jackets. A hive with insufficient numbers of bees may find it difficult to defend a large opening. A smaller opening gives them a fighting chance.
- Entrance reducers are often used in the winter to reduce drafts through the hive, to keep snow and rain from entering, and to discourage small mammals—such as mice—from entering.
- Entrance reducers may be used during treatments with essential oils or organic acids. These treatments—which are alternatives to regular pesticides—are used to control mites. To use them, the beekeeper must make the hive into a fumigation chamber which will contain the compounds. Reducing the entrance is one of several steps that allow these alternative treatments to work.
Size depends on purpose
The size of entrance you select will depend on your purpose as well as the strength of the hive. If you use an entrance reducer during the winter months, it is important to place the opening at the top of the reducer rather than at the bottom (see below). This is so that the entrance does not become blocked by the layer of dead bees that frequently accumulates in cold weather.
The photos below also show that painting the reducers is not a good idea. I painted these and used them during the height of yellow jacket season. The bees were not happy. As you can see, they tried to remove them by chewing. They stripped the paint, rounded the corners, and carved long grooves in the wood. It is obvious now that the entrances were too small for the number of bees in those hives.
Honey Bee Suite