The entrance is where the colony defends itself and where most problems come in. Guards make that opening manageable.

The principle

A colony can only guard a certain length of entrance. If it is wider than the population allows, robbers, wasps and mice get in.

Matching the entrance to the strength of the colony is therefore one of the simplest and most effective measures there is.

The types

• Entrance block or slide: A strip that sets the width; the most used device
• Mouse guard: Lets the bees through but stops mice
• Robbing screen: Makes the entrance not directly accessible; the colony's own bees find the way, robbers do not
• Hornet guards where invasive species occur

When to reduce

• As soon as the flow stops — the usual moment robbing begins
• With weak colonies and nucs
• In late summer, when wasps and hornets build up
• During a dearth
• After moving

The mouse guard

This is the cheapest measure with the highest return in beekeeping.

• Fit it in time, in autumn before the cluster forms; after that the colony no longer guards the entrance
• The size matters; too wide an opening lets a mouse through
• Check for blockage by dead bees through the winter

When to widen

In heat and with strong colonies during a flow. A restricted entrance then hinders flight and ventilation.

What not to do

Close the entrance completely, not even for transport. A closed colony overheats; close with mesh, not a solid plug.

Practical point

Keep the entrance visibly clear of grass and snow. A blocked entrance in winter is a cause of loss that is entirely preventable.