­­­­It has been a while since we checked in on the health of America’s beleaguered honeybees, so let’s take a moment to consider the findings of an annual survey published last week by U.S. Department of Agriculture’s National Agricultural Statistics Service.

The big headline, I think, is that commercial beekeepers’ losses to the mysterious colony collapse disorder (CCD) were down 27.2 percent, year over year, for the first three months of 2017. Because winter is especially hard on ailing bees, the first quarter is usually, though not always, the worst for such die-offs.

Still, the number of colonies lost in the first three months of the year was not small – 84,430 – and significant losses of 34,750 continued in the April-June quarter. That was a very slightly larger improvement over a year earlier, at 27.3 percent.

The pattern for losses from all causes, not just CCD, were quite different – down 13 percent for the winter quarter and 31.5 percent for April-June.

Overall, the commercial honeybee population stood on April 1, the latest date for which statistics are available, at 2.89 million colonies, which was about 3 percent better than the year-earlier figure of 2.80 million.

But that’s a number that beekeepers themselves can control by dividing hives and so on, and more effectively than they can manage losses. Also, it’s driven in part by demand for commercial pollinating services.

So while some coverage of the new report has focused on the slight rise in honeybee population, that’s not nearly so important as the declining loss figures to the long-term prognosis for this important pollinator.

Losses still a challenge

The new findings run parallel on some points to those reported last spring by the Bee Informed Partnership, which found full-year losses among America’s beekeepers – both commercial operators and backyard hobbyists – running at 33 percent for the 12 months ending last April.

While that may seem like a very high number, it was the smallest annual loss figure since 2012; and its wintertime component was the lowest since the survey began in 2006-2007 at the University of Maryland, in response to the first widespread reports of CCD.

In a university announcement of the findings, entomologist and CCD expert Dennis vanEngelsdorp said,

While it is encouraging that losses are lower than in the past, I would stop short of calling this ‘good’ news. Colony loss of more than 30 percent over the entire year is high. It’s hard to imagine any other agricultural sector being able to stay in business with such consistently high losses.

Over the years, the criteria for attributing a colony loss to CCD have been clarified and tightened somewhat. For USDA survey purposes, a CCD event must have all of these elements – in addition to a virtually abandoned hive – to qualify: “1) Little to no build-up of dead bees in the hive or at the hive entrance 2) Rapid loss of adult honey bee population despite the presence of queen, capped brood, and food reserves 3) Absence or delayed robbing of the food reserves 4) Loss not attributable to varroa or nosema loads.”

Those last two factors, a mite and a fungus, are significant parasites on honeybees, and according to the USDA’s new stats varroa mites were “the number one stressor” reported by commercial beekeepers, defined as those who keep five or more hives.

During the spring quarter of 2016, 53.4 percent of commercial colonies were afflicted with the mites, and the number stayed high in the first two quarters of this year, at 42.2 and 41.6 percent.

Other factors that beekeepers reported as significant stressors on their colonies, with figures for last April through June, were non-varroa pests and parasites (16.3 percent), various non-parasitic diseases (9.5 percent), pesticides (12.4 percent), and unknown (4.1 percent). An “other” category, which rolled together harsh weather, starvation, insufficient forage, hive damage and queen failure, was blamed for 12.3 percent of losses.

Complex burdens on pollinators

It’s unclear, at least to me, how the new data may influence a complex national conversation on what we should do to protect the health of honeybees and, by extension, a whole range of other pollinators critical not only to U.S. food production but also to wild plants that anchor natural landscapes (and feed the bees).

The decline of CCD in the latest stats is notable, but these loss rates have shown considerable volatility over the years, and remain  higher than most beekeepers consider acceptable if they’re to stay in business.

I think it’s now generally understood that bees are burdened by many factors that can drive those losses, both alone and in combination; parasites, pesticides and loss of good forage habitat are the consistent leaders on that list, though the rankings will shift around with the viewpoint of the ranker.

Tim May, an Illinois beekeeper and officer in the American Beekeeping Federation, told Bloomberg that it was difficult to clearly attribute his own losses, which varied with hive location and patterns of pesticide spraying:

It’s really tricky. … Maybe it’s pesticides, maybe it’s not. But when I eliminate everything else, it’s a distinct possibility.

We check for mites, we keep our bees well-fed, we communicate with farmers so they don’t spray pesticides when our hives are vulnerable. I don’t know what else we can do.

May Berenbaum, an Illinois entomologist, suggested that it’s time to move on from CCD as a primary concern, calling it “a blip in the history of beekeeping.” On the other hand,

It’s staggering that half of America’s bees have mites. Colony Collapse Disorder has been vastly overshadowed by diseases, recognizable parasites and diagnosable physiological problems.

And speaking to the Detroit Free Press, beekeeper Meghan Malbraith said the overall outlook for major improvement in honeybee health remains discouraging:

We have changed the landscape so much and grow food at scale so we bring in honeybees to pollinate. We have already gotten to places, in large areas of the U.S., where there is no native pollination. Now we are at a point where the backup system is becoming affected.

For the last decade (beekeepers have) been averaging about a 30 percent loss. Beekeepers mostly say about 15 percent would be sustainable. But a few generations ago, if you lost 10 percent, you would want to know why.  A 30 percent loss is completely unsustainable.

We’ve been changing the landscape in ways that make it more difficult for pollinators to thrive for an incredibly long time. Bees are doing poorly because of many decisions made by many people over a long period of time. … We need large scale systematic change on many fronts.

* * *

The full USDA report can be found here [PDF].