Notes:

• You may download the data used for this data explorer from the download page.
• For each operation participating in the survey, the loss rate was calculated as the total number of colonies lost divided by the number of colonies at risk during the season. Colonies at risk were composed of viable colonies, as well as new colonies made or acquired, while excluding colonies sold or parted with. We use two different methods to estimate the loss rate at the population level: weighted and unweighted average, which can be selected using the dropdown menu: "Loss Calculation".
• Loss Calculation: "Weighted average" method: the estimate is calculated as the ratio of the number of colonies lost to the number of colonies managed over a defined period across all participants in the population. This means that each operation is weighted in the population estimate according to the number of colonies they manage. "Unweighted average" method: the estimate is calculated as the average of all operational loss rates. This means that each operation has the same weight in the population estimate. This "unweighted average" is usually more representative of what smaller-scale beekeepers experienced, while the "weighted estimate" tends to represent better large-scale beekeepers, and be a better picture of the estimate of the number of colonies lost at the population level.
• The 95% confidence interval was obtained from a bootstrap resampling of the data (n-out-of-n, 1000 rep). The confidence intervals for the loss estimates were adjusted in August 2020 for all years of data to utilize the bootstrap method which reduces the effect of outliers and generally provides a better representation of the degree of variation in the data.
• Annual loss covers the whole period from one 1 April to the next 1 April ; Summer (1 April – 1 October); Winter (1 October – 1 April).
• Loss rates should not be interpreted as a change in population size because beekeepers can replace lost colonies throughout the year. Therefore, colony loss rates are best interpreted as a turn-over rate, as high levels of losses do not necessarily result in a decrease in the total number of colonies managed in the United States.
• Slight variations, resulting from additional analyses, may occur between reported losses in publications and those shown on this map.
• Responses for beekeepers that manage colonies in more than one state are included in the loss calculation for each state they keep bees in. You can toggle this setting with the dropdown menu: "Operation Type" and select an alternative table showing multi-states operations only or single-state operations only.
• Columns "Beekeepers exclusive to State" (and "Colonies exclusive to State"): shows the percentage of beekeepers (and their colonies) who do NOT keep bees in other state(s) outside of the selected state.
• For the protection of privacy, losses are reported as N/A if 10 or fewer beekeepers responded in that state. These beekeepers' losses are included in the national statistics.

Peer reviewed scientific publications associated with the survey:

Aurell, D., Bruckner, S., Wilson, M., Steinhauer, N., & Williams, G. R. (2024) ‘A national survey of managed honey bee colony losses in the USA: Results from the Bee Informed Partnership for 2020–21 and 2021–22’, Journal of Apicultural Research, 63(1), pp. 1-14. Available at: https://doi.org/10.1080/00218839.2023.2264601

Bruckner, S., Wilson, M., Aurell, D., Rennich, K., vanEngelsdorp, D., Steinhauer, N. and Williams, G.R. (2023) ‘A national survey of managed honey bee colony losses in the USA: results from the Bee Informed Partnership for 2017–18, 2018–19, and 2019–20’, Journal of Apicultural Research, pp. 1–15. Available at: https://doi.org/10.1080/00218839.2022.2158586.

Overturf, K.A., Steinhauer, N., Molinari, R., Wilson, M.E., Watt, A.C., Cross, R.M., vanEngelsdorp, D., Williams, G.R. and Rogers, S.R. (2022) ‘Winter weather predicts honey bee colony loss at the national scale’, Ecological Indicators, 145, p. 109709. Available at: https://doi.org/10.1016/j.ecolind.2022.109709.

Engebretson, J.M., Nelson, K.C., Steinhauer, N., Rennich, K., Spivak, M. and vanEngelsdorp, D. (2022) ‘Perceptions of honey bee management information sources among backyard and sideliner beekeepers in the United States’, Journal of Rural Studies, 96, pp. 190–197. Available at: https://doi.org/10.1016/j.jrurstud.2022.10.020.

Kulhanek, K., Steinhauer, N., Wilkes, J., Wilson, M., Spivak, M., Sagili, R.R., Tarpy, D.R., McDermott, E., Garavito, A., Rennich, K. and vanEngelsdorp, D. (2021) ‘Survey-derived best management practices for backyard beekeepers improve colony health and reduce mortality’, PLOS ONE, 16(1), p. e0245490. Available at: https://doi.org/10.1371/journal.pone.0245490.

Steinhauer, N., vanEngelsdorp, D. and Saegerman, C. (2021) ‘Prioritizing changes in management practices associated with reduced winter honey bee colony losses for US beekeepers’, Science of The Total Environment, 753, p. 141629. Available at: https://doi.org/10.1016/j.scitotenv.2020.141629.

Haber, A.I., Steinhauer, N.A. and vanEngelsdorp, D. (2019) ‘Use of Chemical and Nonchemical Methods for the Control of Varroa destructor (Acari: Varroidae) and Associated Winter Colony Losses in U.S. Beekeeping Operations’, Journal of Economic Entomology, 112(4), pp. 1509–1525. Available at: https://doi.org/10.1093/jee/toz088.

Thoms, C.A., Nelson, K.C., Kubas, A., Steinhauer, N., Wilson, M.E. and vanEngelsdorp, D. (2019) ‘Beekeeper stewardship, colony loss, and Varroa destructor management’, Ambio, 48(10), pp. 1209–1218. Available at: https://doi.org/10.1007/s13280-018-1130-z.

Kulhanek, K., Steinhauer, N., Rennich, K., Caron, D.M., Sagili, R.R., Pettis, J.S., Ellis, J.D., Wilson, M.E., Wilkes, J.T., Tarpy, D.R., Rose, R., Lee, K., Rangel, J. and vanEngelsdorp, D. (2017) ‘A national survey of managed honey bee 2015–2016 annual colony losses in the USA’, Journal of Apicultural Research, 56(4), pp. 328–340. Available at: https://doi.org/10.1080/00218839.2017.1344496.

Seitz, N., Traynor, K.S., Steinhauer, N., Rennich, K., Wilson, M.E., Ellis, J.D., Rose, R., Tarpy, D.R., Sagili, R.R., Caron, D.M., Delaplane, K.S., Rangel, J., Lee, K., Baylis, K., Wilkes, J.T., Skinner, J.A., Pettis, J.S. and vanEngelsdorp, D. (2015) ‘A national survey of managed honey bee 2014–2015 annual colony losses in the USA’, Journal of Apicultural Research, 54(4), pp. 292–304. Available at: https://doi.org/10.1080/00218839.2016.1153294.

Lee, K.V., Steinhauer, N., Rennich, K., Wilson, M.E., Tarpy, D.R., Caron, D.M., Rose, R., Delaplane, K.S., Baylis, K., Lengerich, E.J., Pettis, J., Skinner, J.A., Wilkes, J.T., Sagili, R., vanEngelsdorp, D. and Partnership, for the B.I. (2015) ‘A national survey of managed honey bee 2013–2014 annual colony losses in the USA’, Apidologie, pp. 1–14. Available at: https://doi.org/10.1007/s13592-015-0356-z.

Steinhauer, N.A., Rennich, K., Wilson, M.E., Caron, D.M., Lengerich, E.J., Pettis, J.S., Rose, R., Skinner, J.A., Tarpy, D.R., Wilkes, J.T. and vanEngelsdorp, D. (2014) ‘A national survey of managed honey bee 2012-2013 annual colony losses in the USA: results from the Bee Informed Partnership’, Journal of Apicultural Research, 53(1), pp. 1–18. Available at: https://doi.org/10.3896/IBRA.1.53.1.01.

Spleen, A.M., Lengerich, E.J., Rennich, K., Caron, D., Rose, R., Pettis, J.S., Henson, M., Wilkes, J.T., Wilson, M.E., Stitzinger, J., Lee, K., Andree, M., Snyder, R., vanEngelsdorp, D., and for the Bee Informed Partnership (2013) ‘A national survey of managed honey bee 2011–12 winter colony losses in the United States: results from the Bee Informed Partnership’, Journal of Apicultural Research, 52(2), pp. 44–53. Available at: https://doi.org/10.3896/IBRA.1.52.2.07.

vanEngelsdorp, D., Caron, D., Hayes, J., Underwood, R., Henson, M., Rennich, K., Spleen, A., Andree, M., Snyder, R., Lee, K., Roccasecca, K., Wilson, M.E., Wilkes, J., Lengerich, E. and Pettis, J. (2012) ‘A national survey of managed honey bee 2010-11 winter colony losses in the USA: results from the Bee Informed Partnership’, Journal of Apicultural Research, 51(1), pp. 115–124. Available at: https://doi.org/10.3896/IBRA.1.51.1.14.

vanEngelsdorp, D., Hayes, J., Underwood, R.M., Caron, D. and Pettis, J. (2011) ‘A survey of managed honey bee colony losses in the USA, fall 2009 to winter 2010’, Journal of Apicultural Research, 50(1), pp. 1–10. Available at: https://doi.org/10.3896/IBRA.1.50.1.01.

vanEngelsdorp, D., Hayes, J., Underwood, R.M. and Pettis, J.S. (2010) ‘A survey of honey bee colony losses in the United States, fall 2008 to spring 2009’, Journal of Apicultural Research, 49(1), pp. 7–14. Available at: https://doi.org/10.3896/IBRA.1.49.1.03.

vanEngelsdorp, D., Hayes, J., Underwood, R.M. and Pettis, J. (2008) ‘A Survey of Honey Bee Colony Losses in the U.S., Fall 2007 to Spring 2008’, PLoS ONE, 3(12). Available at: https://doi.org/10.1371/journal.pone.0004071.

vanEngelsdorp, D., Underwood, R., Caron, D. and Hayes, J. (2007) ‘An estimate of managed colony losses in the winter of 2006-2007: A report commissioned by the apiary inspectors of America’, American Bee Journal, 147(7), pp. 599–603. Available to download here.