Sometimes a swarm builds no nest in a cavity but hangs exposed and builds comb in the open — on a branch, a roof edge or under an overhang.

Why it happens

• No suitable cavity found: The scouts found nothing within range
• A swarm that waited too long and began building where it hung
• A warm climate, where protection from cold is less essential

With western honey bees in a temperate climate it is unusual; in warm regions and with some related species it is the normal nest form.

Why it usually fails

An exposed nest has no protection against:

• Rain: The comb gets wet and the brood chills
• Wind: The comb tears or breaks away
• Cold: The cluster loses heat on every side
• Predation: The nest lies open

In a temperate climate such a colony almost never survives the winter.

What you can do

Transferring the colony to a hive is generally the only way to save it.

• Work in the evening, when all the bees are home
• Cut the comb sections free and tie them into empty frames
• Find the queen; without her the colony returns to the old site
• Brush the remaining bees into the hive
• Place the hive where the nest hung, so stragglers find it

The unknown

As with any collected swarm the origin is unknown: disease, Varroa and genetics are all unknown.

Keep the colony apart until it is clear it is healthy.

The opportunity

If the nest is young and has no sealed brood, all the mites are on the bees — the most favourable moment for a contact treatment there is.

What it tells you

A colony nesting in the open indicates too few suitable cavities in the area. For anyone wanting to catch swarms, that is useful information: a well-placed bait hive fills that gap.