Winter Loss Survey 2011 – 2012: Preliminary Results

Note: This is a preliminary analysis, and a more detailed final report is being prepared for publication at a later date.

April 25, 2012

Dennis vanEngelsdorp1, Jeffery Pettis2, Karen Rennich1, , Robyn Rose3 , Dewey Caron4, Keith S. Delaplane5, James T. Wilkes6, Eugene J. Lengerich7, Kathy Baylis8, and the Bee Informed Partnership.

The Bee Informed Partnership (, in collaboration with the Apiary Inspectors of America (AIA) and the United States Department of Agriculture (USDA) conducted an online survey to estimate honey bee colony losses for the 2011/2012 winter season. A total of 5,543 U.S. beekeepers responded, approximately 20% of the beekeepers in the United States. Collectively, responding beekeepers managed over 14.6% of the country’s estimated 2.49 million colonies.

Preliminary survey results indicate that 21.9% of managed honey bee colonies in the United States were lost during the 2011/2012 winter. This represents a substantial improvement in mortality compared to the previous 5 years when losses of approximately 30% were recorded. Previous survey results found a 30% total colony loss in the winters of 2010/2011, 34% in 2009/2010, 29% in 2008/2009, 36% in 2007/2008, and 32% in 2006/2007.

On average, beekeepers lost 25.3% of the colonies in their operation. This is a 13.1 percentage point or 34.0% decrease in the average operational loss experienced by U.S. beekeepers during the winter of 2010/2011 when they reported an average loss of 38.4%. Almost half of responding beekeepers (46%) reported losses greater than 13.6%, the level of loss that beekeepers stated would be acceptable.

Colony Collapse Disorder (CCD) is a phenomenon in which the entire colony of bees abruptly disappears from its hive. Of beekeepers surveyed who reported losing colonies, 37% lost at least some of their colonies without the presence of dead bees. While we cannot confirm that these colonies had CCD, these respondents reported higher average colony losses (47%) than respondents who lost colonies but did not report the absence of dead bees (19%).

The winter of 2011-2012 was unseasonably warm with NOAA ranking January as the fourth warmest in U.S. history. This could have favorably impacted colony survival this past year.

The Bee Informed Partnership is funded by the National Institute of Food and Agriculture, USDA.

1. University of Maryland; 717-884-2147;
2. USDA-ARS Bee Research Laboratory, Beltsville, MD
3. USDA APHIS Plant Protection and Quarantine, Riverdale, MD 20737
4. University of Oregon, Corvallis, OR
5. University of Georgia, Athens , GA
6. Appalachian State University, Boone, NC
7. The Pennsylvania State University, Hershey, PA
8. University of Illinois, Urbana-Champaign, IL

Written By: The Bee Informed Team

has written 50 post in this blog.

The Bee Informed Partnership is a collaboration of efforts across the country from some of the leading research labs and universities in agriculture and science to better understand honey bee declines in the United States. Supported by the United States Department of Agriculture and the National Institute of Food and Agriculture, we’re working with beekeepers to better understand how we can keep healthier bees. The key to our success is the true partnership we maintain across a wide range of disciplines including traditional honey bee science, economics, statistics, and medical research that makes all these tools available to this important research. And just as important as the tools are the people. We not only have the leading researchers in the honey bee industry, we also have advisory boards from the commercial beekeeping industries, almond and other commercial growers, as well as naturalists and conservationists from across the country.