The correct term that has been used for a long time that everyone knows and understands is “Uniting”, not “combining”, “merging”, “amalgamating”, “joining” or any of the other terms that have crept into beekeeping in recent years. I think these have come from inexperienced people who have tried to teach or write books before they have the knowledge to do so, or are aware of the correct terminology.

This blog provides a focus for methods and equipment that can be used to unite colonies, nucs or a single frame of bees.

There are many different circumstances when it is advisable to unite groups of bees, such as:-

To reduce colony numbers, where manipulations have resulted in extra colonies, or the beekeeper is downsizing.
Make a colony from two or more that is strong enough to have a chance of wintering that wouldn’t survive on their own.
Because of a shortage of queens at the end of the season, such as queen rearing nucs, where there may have been failed matings.
A colony has been queenless, had a drone layer or laying workers.
A colony has been artificially swarmed (or similar operation) and the two resulting colonies are brought back together.
To requeen a colony.
There are many other reasons, but whatever it is, here are some simple rules that you may find helpful:-

If put together immediately on combs, bees from two colonies will probably fight, three or more usually won’t.
If there is no physical barrier, e.g. newspaper, bees from one colony may kill a queen from another, unless she is caged.
Disorientation, confusion and a common smell will often make direct introduction possible.
Make sure none of the colonies are diseased, especially foul brood.
The resulting colony, if united in the autumn, should be strong enough to overwinter. If not, then add frames of sealed brood at intervals from other colonies until it is strong enough.
Two or more swarms can be united by dumping them on a board in front of a hive together.
A swarm can be used to bolster another colony, but it is preferable to remove the queen in the colony a couple of hours before, or to cage her if you want to retain her and kill the queen in the swarm.
The “newspaper bag” method is used to unite a frame of bees to an existing colony. Such an additional frame may have a queen for requeening purposes or not as the case may be.