A 7th revision post for the British Beekeeping Association’s Module 1 exam, Honey bee Management, which I’m taking in March. Moving to 1.13 on the syllabus:

“The Candidate shall be able to give a detailed account of:-

the drifting of honeybees, the dangers caused and techniques used to minimise the problem;”

Drifting occurs when worker bees, usually returning foragers, or perhaps young bees on their first orientation flights, accidentally drift into a hive close to their own. They will have an unfamiliar smell to that colony’s guard bees, but if they are carrying nectar or pollen and display submissive body behaviour they are likely to be let in. Ted Hooper, in ‘Guide to Bees and Honey‘ (2010), p39, gives us this description of guard bee behaviour towards drifters:

“a drifting bee entering the colony by mistake, perhaps because it has been blown down to the hive by a cross wind, or misled by a similarity of the approach picture, will be challenged. In this case the guard will press the challenge because the smell of this bee is not the right one. The drifter, because its instinct says it is in the right place, will not try to fight the guard but will submit. If the drifter is facing the guard it will offer food, which the guard will usually ignore. If the guard is attacking from the side […] the drifter will tuck its tail in and stand quiet, with its head tucked down, or it may rear on to its two back pairs of legs, extending its tongue and strop this with its front legs. These patterns of behaviour denote submission and the guard […] will do no real harm and certainly not attempt to sting. As with all bees, the guard’s concentration period is short, and in a few seconds it gets tired of the whole affair and lets the drifter proceed”

If you’re not very impressed by the rather lackadaisical bouncer skills of the guard bees Ted describes above, take a look at this landing board view video for a sense of the amount of bee traffic guard bees might be dealing with during a nectar flow: http://www.youtube.com/watch?v=5tZ607q-OHA. The Italian honeybee Apis mellifera ligustica, the most popularly kept bee worldwide, is thought to have a greater tendency to drift than other bees (as well as being renowned robbers of other colonies).

The problem with the innocent behaviour of drifters is that they can spread disease and parasites, whether American Foul Brood (AFB) spores or varroa. A newly mated virgin queen who mysteriously goes missing could have drifted into the wrong hive. A less serious issue is that it can result in uneven numbers of bees in an apiary’s hives, as a result of bees returning to some colonies more often than others.  This can weaken some hives whilst making others stronger, resulting in the colonies requiring different management for swarm control, super adding, harvesting etc (more troublesome if you have twenty hives than if you have two).

In his book ‘Practical Beekeeping‘ (1997), Clive de Bruyn remembers

 “a time when local beekeepers from Manchester and Sheffield used to place their hives on the north Derbyshire moors in long lines. It was the boast of one old time beekeeper that he always got the best honey crops by being the last one to place his hives. By placing them at the ends of the stocks already there his colonies benefited from the extra foragers he collected.”

I can just imagine that old Northern beekeeper chuckling cannily to himself. Do the hives still get lined up across the moors, does anyone know?

To reduce drifting, beekeepers can paint hive entrances different colours and provide distinctive landmarks in front/nearby to hives (perhaps a big branch or shrub). Hives should be positioned with their entrances facing in slightly different directions – in a circle, with hives facing outwards is recommended – and as far apart as possible, preferably 1.2 – 1.5 metres apart. Ted Hooper suggests facing the hives towards cover between 4-6 feet away, such as a hedge, to provide calm air in front of the hives so bees are not blown off course as they try to land.

Barnsley Beekeepers Association use the below photo on their website as an example of a set up which could cause drifting (http://barnsleybeekeepers.org.uk/apiary.html), as the hives are lined up close together in a row all facing the same direction, towards a fairly flat nondescript looking field.

An example of different coloured hives – Michael Bush’s hives, photo from www.bushfarms.com. The best colours to use are black, white, blue and yellow (bees are red colour-blind so do not use red).

The hives of a church in Gradišče Pijavo Gorizia, Slovenia, also making use of blues and yellows to differentiate the hives for the bees.

EDIT: As Chris reminded me in his comment below, drones deliberately pay visits to other hives, where the workers welcome them in and feed them. I like to think they are hunting out virgin queens about to go on their first mating flights, so they can get a head start in the chase. Nothing much can be done to prevent this deliberate drifting, as opposed to the accidental drift of a returning forager.

References:

• Guide to Bees & Honey, Ted Hooper (2010)
• Keeping Healthy Honey Bees, David Aston & Sally Bucknall (2010)
• Module 1 Study Notes, Mid Bucks Beekeeping Association (2012)
• Practical Beekeeping, Clive de Bruyn (1997)
• The Honey Bee Around & About, Celia Davis (2007)

Useful blog posts:

• Drifting in honeybees – The Apiarist, December 2015. Discusses research into drifting by American Foul Brood infected bees and also how frequently drones drift compared to workers.