Nearly one in four honeybee colonies in the Netherlands did not survive the winter of 2025–2026, according to a new national survey.
Researchers say the losses continue a worrying trend, with winter deaths remaining above 20% for the fourth year in a row.
The survey found that 24% of Dutch honeybee colonies were lost over the winter.
The findings come from an annual study carried out by researchers at Wageningen University & Research (WUR) together with several Dutch beekeeping organizations.
The survey was conducted on behalf of the Dutch Ministry of Agriculture, Fisheries, Food Security and Nature.
Honeybees play a vital role in pollinating flowers, fruits and many food crops. Healthy bee populations are important for both nature and agriculture.
When large numbers of colonies die during winter, it becomes harder for beekeepers to rebuild their hives, and pollination services can be affected.
The study showed that winter losses were not the same across the country. Some regions experienced much higher losses than others. Groningen recorded the highest winter mortality, with 41.5% of colonies dying.
In contrast, Overijssel had the lowest losses at 16.9%, meaning most colonies there survived the winter. Other provinces, including Zeeland, Utrecht and North Holland, also reported winter losses that were slightly above the national average.
Researchers do not yet know exactly why some regions perform better than others. They believe that differences in local weather, the environment, food availability and beekeeping practices may all play a role.
There is no single reason why bee colonies die during winter. Instead, several problems can combine to weaken a colony before the cold season arrives. One of the biggest risks is losing the queen bee.
Without a healthy queen, a colony usually cannot survive. Food shortages, diseases and colonies that are already weak before winter also increase the chance of death.
Another major threat is a tiny parasite called the Varroa destructor mite. These mites feed on honeybees and spread harmful viruses that weaken entire colonies.
Because of this, controlling Varroa mites remains one of the most important tasks for beekeepers. The survey found that 86.9% of Dutch beekeepers treated their colonies for Varroa mites before winter, a figure similar to previous years.
Researchers are also watching the spread of the Asian hornet, an invasive species that hunts honeybees and other insects to feed its young. While scientists cannot yet say how much the hornet contributed to winter losses, its presence is increasing rapidly.
In 2024, about one in four beekeepers reported seeing Asian hornets nearby. By 2025, that number had risen to more than half of all beekeepers surveyed. Researchers expect the hornet’s impact on honeybee populations to grow in the coming years.
This year’s survey included 840 Dutch beekeepers, representing almost 8% of the country’s estimated 11,000 beekeepers. More than half of those who took part said all of their colonies survived the winter, while 7% lost every colony they owned.
The researchers say these yearly surveys provide valuable information about the health of honeybees and help identify the biggest challenges facing beekeepers.
By understanding the causes of winter losses, scientists and beekeepers hope to develop better ways to protect honeybee colonies and support these essential pollinators in the years ahead.
