Entrance Guards and Reducers

Hive entrance guards are parts fitted to the hive entrance that let bees keep coming and going while keeping out external threats such as mice, wasps and hornets, robber bees and cold. The most common are the entrance reducer, the mouse guard, the hornet guard and the robbing screen. They all share one rule: a guard should stop only the unwanted visitor, without blocking the bees.

Why should the hive entrance be protected?

The entrance (flight entrance, hive mouth) is the hive's only door, and every danger comes in through it. Guard bees defend the entrance; but if it is wider than the colony can defend, the defence collapses. Guards let you adjust the size and shape of the entrance to the season and the threat:

• Robbing: When the nectar flow stops, strong colonies rob weak ones. A narrow entrance makes it easier for the guards to defend.
• Rodents: In autumn, mice want to nest in the warm, food-filled hive; they tear up the combs and disturb the cluster.
• Wasps and hornets: In late summer and autumn, wasps and hornets hunt bees in front of the entrance or try to get inside; in the south and west of Türkiye, Vespa orientalis is a particular problem.
• Cold and wind: In winter, a wide entrance increases the amount of air the cluster has to heat.

What types of hive entrance guard are there?

Entrance reducer (entrance block)

A wooden block, or a metal or plastic slide, inserted into the entrance between the floor and the brood box, with one or two openings of different widths. The entrance width is changed by turning the block or sliding the slide.

• Narrow opening: For a weak colony, a new split, a swarm, the robbing season and winter.
• Wide opening: For a medium-strength colony or the transition into spring.
• Removed completely: For a strong colony during a nectar flow and in hot summer; full ventilation and easy traffic.

Mouse guard

A metal strip nailed or clipped across the front of the entrance, with round holes just large enough for a bee (about 9–10 mm). Bees pass through the holes; mice cannot get in.

• It should be fitted in autumn, before the first cold spell. A guard fitted after a mouse has got into the hive and made a nest traps the mouse inside.
• It is removed in spring when the colony grows and traffic increases; otherwise foragers may have their pollen loads scraped off in the holes, and removing dead bees becomes harder.
• It should be stainless steel or galvanised, and its edges must not injure the bees.

Hornet guard

Wire or plastic devices fitted in front of the entrance, with narrow slots that bees can pass through but large hornets cannot. Some models form a small cage (porch) in front of the entrance; even if a hornet gets into this cage, it cannot reach the hive entrance, and the guard bees defend inside the cage.

• It is fitted in late summer, when hornet pressure begins.
• The slot size must suit the local wasp or hornet species; a guard designed for large species may not stop small ones.
• A guard alone is not enough: locating wasp and hornet nests around the apiary in line with local regulations and safe trapping are also needed.

Robbing screen

A device that covers the front of the entrance with mesh and gives the bees access from the top or side edge of the screen. The colony's own bees quickly learn the new entrance, while robber bees, which follow the scent straight to the entrance, hit the mesh screen and cannot find the way in. It is very effective when robbing has started or is expected, and on weak hives. The way a robbing screen redirects bee traffic is described in detail on the “Hive entrance diverters” page.

Seasonal calendar for entrance guards

Closing the entrance for moving and other operations

In migratory beekeeping or when moving a hive, the entrance is closed completely. The slides and closing blocks used for this are a kind of temporary guard.

1. Closing is done in the evening, after the foragers have returned to the hive.
2. Ventilation is essential in a closed hive: the front of the entrance is closed with mesh, or a mesh-covered ventilation opening is used. A strong colony left without air can suffocate in the heat.
3. After the hive has been placed at its new site and left to settle for a while, the entrance is opened calmly.

What should you look for when choosing an entrance guard?

• Size fit: It must match the height and width of your hive entrance exactly; a guard that leaves gaps at the edges is useless.
• Material: Stainless steel or galvanised metal, durable plastic or well-seasoned wood; no paints or coatings that are harmful to bees.
• Easy fitting and removal: It should be possible to fit it without opening the hive or upsetting the bees.
• Cleanability: Build-up of dead bees and propolis should be easy to clean off.

Common mistakes

• Fitting a mouse guard after a mouse has already got in.
• Closing the entrance completely in winter; the bees cannot make cleansing flights and moisture cannot escape.
• Being too late in reducing the entrance once robbing has started; once robber bees have learned the way, they are harder to stop.
• Insisting on a narrow entrance in summer for a strong colony; congestion at the entrance, overheating and the tendency to swarm increase.
• Forgetting to remove guards in spring.