The survey, including more than 7,000 beekeepers across the U.S., found that nearly 24 percent of their colonies perished over the winter. That’s down from about 30 percent the year before but up from 22 percent in 2011-2012. Apiarists considered a loss of roughly 19 percent to be acceptable this year, meaning that this past winter’s losses were six points higher than what beekeepers deem acceptable. “While we’re glad to see improvement this year, losses are still too high and there is still much more work to be done to stabilize bee populations,” U.S. Department of Agriculture Secretary Tom Vilsack said in a statement.
In the same statement, Jeff Pettis, a coauthor of the survey and a research leader at the Agricultural Research Service (ARS) Bee Research Laboratory in Beltsville, Maryland, said it’s unclear why bee colonies fared a bit better this winter, but that many factors play a role, “such as viruses and other pathogens, parasites like varroa mites, problems of nutrition from lack of diversity in pollen sources, and even sublethal effects of pesticides combining to weaken and kill bee colonies.”