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Where this comes from. The National Bee Unit’s leaflet on pests, diseases and disorders of adult bees, its fact sheet on starvation, its guideline on disease recognition and Starting Right with Bees, with two Scottish Beekeepers’ Association documents for the winter routine. Sources at the foot of the page.
Some dead bees are normal
In summer a worker lives about six weeks, and in winter up to six months. Through the winter the queen lays little or nothing, so the bees that die are barely replaced. 2 A few dead bees on the landing board or the ground in front of the hive are to be expected.
In autumn, some of them will be drones. Drones live for several months in summer but are thrown out of the colony as winter approaches. Drones are larger, heavier and stockier than workers. 2 Finding them at the entrance in autumn is expected.
What matters is how many, how they are lying, and what they look like. The rest of this guide is the signs that mean something.
Keep the entrance clear
Dead bees can build up on the floor and block the entrance. 3 One experienced Scottish beekeeper clears them from the entrance with a piece of bent wire. 4 Clear debris from the entrance, but leave snow: it is porous, and it keeps the bees from being tempted out on a bright, cold day. 5
Keeping the grass short in front of the hive makes it much easier to see what is being carried out. 1
A pile, with crawling bees on top
This is the one to act on straight away. When a colony is on the edge of starvation, the dead may be piled on the floor deep enough to block the entrance, with starving bees crawling slowly over the top. Inside, the cells round the brood nest are dry, and bees may be dead head first in the cells. 3 Bees on the brink of starvation need feeding without delay. 3 Starvation and emergency feeding has how.
Black, shiny, trembling bees
Trembling bees, and bees that look black, shiny and hairless, are the characteristic sign of chronic bee paralysis virus. Sick bees are pushed out of the entrance, and as the disease goes on, dead bees and bees that cannot fly build up on the floor of the hive and outside the entrance. A large pile can form. 1
If you also see dysentery, dark shiny bees and a lot of dead bees together point to chronic bee paralysis as the likely cause. 1 Widening the entrance can help the colony clear the dead, and the leaflet has the rest. 1
Dead bees spread across a wide area
Poisoning looks different. Poisoned bees lie spread out over a wide area, and dying ones may spin on their backs, where bees with chronic bee paralysis are mostly in or right by the hive, lethargic and shaking. 1
If you suspect poisoning: 1
- Contact the National Bee Unit or your local bee inspector.
- Note the weather, any spraying or treatment of insect nests nearby, and any flea treatment you have put on a pet.
- Take dated photographs or video of the apiary and the bees, because things may have changed by the time an inspector arrives.
- Protect the dead bees on the ground from the weather, for example with an upturned tray or dustbin lid. Be careful handling them, and do not put them in your food freezer.
Bees crawling in the grass
Bees crawling up grass stems in front of the hive, confused and unable to get back in, can be a sign of tracheal mites, but the same behaviour comes with other problems, Nosema among them. 1 One form of Nosema shows as dead bees outside the hive, bees crawling on the grass, and abnormally small adult bees. 1 Tracheal mites can only be reliably diagnosed under a microscope. 1 If you are seeing this, ask your local bee inspector or association for help.
Crumpled wings
Bees with deformed wings mean a high level of deformed wing virus, which varroa spreads, and a heavy mite load. Dead bees with their tongues out, caught as they were emerging from their cells, are another sign of the same problem. 6 Varroa treatment after the honey covers what to do, and A dead colony: what happened reads the evidence if a colony has already gone.
The short version
- A few dead bees, and drones in autumn, are normal.
- Keep the entrance clear of dead bees and debris, but leave snow alone.
- A pile blocking the entrance with crawling bees on top: starvation, feed today.
- Black, shiny, trembling bees and a growing pile: chronic bee paralysis.
- Dead bees spread wide, some spinning: suspect poisoning and call the National Bee Unit.
- Crawling in the grass or crumpled wings: get help pinning down the cause.
This guide is general information, not legal advice. Rules change - always check the current guidance on GOV.UK before relying on it.