Entrance reducers are used on hives to discourage robber bees. Weaker hives don’t have enough bees to protect the entrance & an unguarded entrance is an open door for invasion. If your entrance is too large, more guard bees are assigned to protect it. This prevents them from doing more productive tasks within the hive. In our hives, we use them mainly during warmer months of Spring - Fall. During colder months, mouse guards are used.
Entrance reducers can be made of wood, plastic, or metal. We do not recommend wood reducers because they block air flow & encourage burr combing. In our hives we use a strip of #8 hardware cloth. This hardware cloth comes in a roll & can be purchased at Lowe’s or Home Depot. Use wire cutters to cut the cloth into a strip that will cover the entire width of the entrance & about 2” in height. Staple the wire over the entrance. If your hive is empty awaiting bees leave the entrance closed to prevent unwanted visitors & to protect any honey stores. For established or newly established hives, bend the wire back about one inch. For stronger hives & during good nectar flows you can bend the wire back further to prevent traffic jams.