Colony losses explained

What a loss survey actually measures

The headline loss figures come from voluntary surveys in which beekeepers report how many colonies they had going into winter and how many came out. That is a specific measurement with specific limits, and almost every misreading follows from ignoring them.

• It is beekeeper-reported, not independently verified, and respondents self-select — the people who answer surveys are not a random sample of beekeepers.
• It covers ONE country, or sometimes one region, in ONE season. A loss rate from one national survey is not a global figure and moves substantially year to year.
• The definition of a loss varies between surveys — whether a colony that dwindled but survived counts, whether queen failure counts separately, whether losses in transit are included.
• It measures colonies, not bees, and a colony is a unit of husbandry rather than an organism.

None of this makes the surveys useless. They are the best instrument available for a real problem, they have been run consistently enough to show trends, and a loss rate that stays high for two decades is telling you something. It simply is not telling you what the phrase 'a third of bees died' implies.

Why the number does not mean extinction

The real consequence falls on beekeepers rather than on the bee. Replacing a third of your colonies every year is a substantial recurring cost in money, labour and forgone production, and it is the reason a loss rate is worth tracking even though nothing is going extinct.

It is also worth saying that this is not new. Beekeepers lost colonies over winter long before anybody surveyed it — disease, starvation, queen failure and hard winters are old problems. What is arguable is whether current rates are higher than historical ones, and the honest answer is that the historical baseline is poorly measured because nobody was systematically counting.

What the US quarterly numbers show

The United States is the one country with an official quarterly count of managed colonies, losses, additions and renovations, run by the USDA since 2015 for operations with five or more colonies. It shows the replacement described above as it happens. In January to March 2026, operations lost 454,890 colonies — 16 per cent of those they started the year with — and added 464,320 in the same quarter. The number of colonies on 1 January has stayed between about 2.6 and 2.9 million in every year from 2018 to 2026.

The same survey asks which stressors affected colonies during each quarter. Varroa has been the most commonly reported stressor in every quarter recorded — though the share of colonies reported as affected has fallen from between 40 and 56 per cent in 2018 to around 22 to 28 per cent in 2025 and 2026. The survey records what beekeepers report affecting their colonies, not what killed them, and it cannot say why the reported share has fallen.

Northern Ireland: a regional survey, read on its own terms

The Agri-Food and Biosciences Institute runs a beekeeping husbandry survey in Northern Ireland, with the COLOSS research network, and has done for eighteen years. For the winter of 2025-26, 101 beekeepers reported on 570 production colonies, and 130 were lost — 23%, against 33% the winter before and 24% in 2023-24. The series has run from a low of 9% in 2013-14 to a high of 43% in 2012-13. Nearly half of the respondents, 48%, lost no colonies at all.

How the losses were classed matters as much as how many there were. Beekeepers put 66 of the 130 down to unsolvable queen problems, 50 to colonies found dead or empty, and 14 to natural hazards — storm, flood, theft or wasps. Of the 50 dead colonies, beekeepers described 20 with workers dead head-first in cells while food was still present, 8 dead in cells with no food left, and 18 with only a few dead bees. Those are descriptions, not diagnoses: the survey records what the respondent saw and how they classed it.

What is driving them

The consensus is that no single cause accounts for the pattern, and that the interaction is the point. Varroa and the viruses it amplifies are consistently identified as a leading factor in regions where the mite is established; poor nutrition from monotonous or scarce forage, pesticide exposure, queen failure, weather and management practice all appear in the literature and in beekeeper reporting.

Attributing a given loss to one cause is genuinely hard, because the pressures compound: a colony carrying a heavy mite load, on poor forage, hit by a bad autumn, fails for all three reasons at once. Any account that names one villain is simplifying past the evidence — and this is equally true of accounts naming pesticides alone and accounts naming varroa alone.

And it is not the same question as wild pollinator decline

Managed colony losses and wild bee decline are different problems with different evidence, different drivers and different remedies. Wild bees are not replaced by a beekeeper in spring. HoneyHQ keeps them on separate pages for that reason, and the pollinator-decline guide is where the wild side is assessed.