How do robber screens work? The idea is simple. Robbers attempt to enter the hive by flying straight into the entrance. The screen prevents them from entering. Resident bees leave the entrance, crawl up the hive front and exit through one of two slots in the top of the screen. They re-enter the hive through the same slots.
A top gate and an adjustable lower entrance allow the robber screen to also be used as a reduced standard entrance by sliding the reducing screen to close off part of the lower entrance. With the lower entrance closed it serves as a ventilated closure for moving bees.
The reducer screen also features a built in mouse guard. Just flip it over and it serves as a winter entrance with mouse protection. The robber screen is available in sizes to fit 8 and 10 frame hives.
Hint: Install your robber screen when the bees are in for the day, either early in the morning or late in the evening. This will allow resident bees to learn the new entrance and not trap them outside the colony.