Every year I get an email from the Bee Informed Partnership. They’re asking for beekeepers to fill out a 20- to 30-minute survey on our practices and results in our bee yards. As far as I know, this is the most comprehensive and popular survey of beekeeping in the US, netting an estimated 11 percent of the US’s 2.69 million managed hives. They just released the results of last year’s survey.
The Big Picture
The headline version of this report is that winter losses are up from the 10-year average and from last year.
During the 2018-2019 winter (1 October 2018 – 1 April 2019), an estimated 37.7% of managed honey bee colonies in the United States were lost (Fig. 1). This loss represents an increase of 7 percentage points compared to last year (30.7%), and an increase of 8.9 percentage points compared to the 13-year average winter colony loss rate of 28.8%. This year’s estimate is the highest level of winter losses reported since the survey began in 2006-2007. [emphasis added]
But while winter losses were up, annual losses were relatively steady over the last few years. It is interesting that beekeepers’ perceptions of what are acceptable losses are rising steadily as we experience higher percentage losses as a regular course.
The Local Picture
Wisconsin fared better than most places, coming it at sixth overall for colony survival, as can be seen on this nifty interactive map, with “only” 31 percent losses last year.
What I am particularly interested in, however is the data sorted by the many variables asked about in the management survey. These data are tabulated in an interactive interface on the Bee Informed website. Below, I’m including the graph showing that people who did not treat had greater winter mortality than those who did treat for Varroa mites with chemicals. While one might be tempted to think that this means we should all be treating, actually the opposite is true. Only about 8 percent more hives died without treatment, meaning that the majority of hives can survive without it, and if those survivors are split and bred, honey bees’ overall ability to survive with mites will go up, whereas when one treats, those eight percent of hives that would have died will be allowed to contribute their non-Varroa-tolerant genes to the pool.
Over the next week, I’ll be posting a step-by-step guide describing how to split and manage your hives without treatment and improve your local bee genetics.