2023-24 Survey Reports

** Looking for a report in your specific region?  Refer to the Individual Club Reports page.

** Scroll down to see the Washington Backyard Beekeepers Winter Bee Loss Report, 2023-24 or click here to view Washington as PDF.


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Winter Bee Losses of Oregon Backyard Beekeepers for 2023-2024

by Dewey M. Caron

Click here to view a PDF of Oregon report.

Overwintering losses of small-scale Oregon backyard beekeepers decreased dramatically to 20% this winter, the lowest percentage loss in 15 years of Oregon hobbyist/backyard beekeeper surveys. This annual survey: www.pnwhoneybeesurvey.com. Herein we discuss the data provided by 171 Oregon beekeepers, only 2/3rds of the number last year and well below the previous 5-year average of 305 respondents.  Results of the 121 Washington respondents completing surveys (the average response rate of the last few years) are included in a separate loss report. Washington’s average loss was 31%, also the lowest ever reported.

2023 -24 State/Club Losses

Club results of 13 local Oregon associations are shown in Figure 1. Colony numbers ranged from 1 to 41 colonies in Oregon (average 5.7 colonies same as last year; medium number = 4 colonies, also same as last year). The number of respondent individuals are listed next to the association name. The bar length is the average club loss percentage for the year. 

Overwinter losses of members of different organizations varied from a low of 10% for the 31 Willamette Valley and Lane Co beekeeper respondents to a high of 39% for the 7 Central Coast members. The 4X range of losses was the same as two years but less than the previous year (3X difference). Approximately 80% of respondents are roughly along the I-5 corridor between California and Washington.

2023-2024 Overwinter Losses by Hive Type

The loss statistic was developed by asking the number of fall colonies and surviving number in the spring by hive type. Respondents had 988 fall hives (345 fewer of the respondent number last year) of which 788 survived to spring (200 lost), equating to a 20% loss (80% survival rate). This was 10 percentage points greater survival over the previous winter loss rate. Ninety-seven percent of hives were 8-frame or 10-frame Langstroth hives, nucs or (49) long hives. There were 49 fall nucs (27% loss rate). Among non-traditional hive types were 24 top bar hives (17% loss) and 12 Warré hives (25% loss).  Other hive types in addition to long hives included Layens, log, Apamaye, pagoda and Slovenian.  

The winter losses of PNW 8-frame Langstroth hives was a single percentage point greater compared to the loss rate of 10-frame Langstroth hives. The loss rates of Langstroth 8 and 10 frame hives over the past 8 years has averaged 36% for 8-frame Langstroth hives and 40% loss for 10-frame hives respectively but the last 2 years the losses have been within a single percentage point of each other. Nuc losses are typically higher than losses of 8 or 10-frame Langstroth hives, this year 7 percentages point greater. The Nuc 9-year average loss is 43%. This year’s Top Bar hive loss of four colonies (17%) is below the 9-year average top bar hive loss of 48%. The 2023 Warré hive loss rate of 25% is below the 8-year average of 41%. 

2023-2024 Loses Based on Hive Origination

We also asked survey respondents to characterize their loss by hive origination. The result is graphically presented below. Overwintered colonies obviously had the best survival (13%) with the 160 splits/divides and 1114 swarms also with excellent survival. Packages (39% loss) and nucs (33%) were higher with package bee survivals exhibiting triple the loss rate of the overwintered colonies. The origination loss percentages are relatively the same each year. This season overwintered colonies had a survival rate much better than most winters.

2023 -24 Individual Hive Losses

Forty-seven percent (81 individuals) of Oregon respondents had NO LOSS overwinter (total of 366 colonies), an increase of 11 1/2 percentage points compared to last year. One quarter of that number, 12% (20 individuals – 40 colonies) lost 100% of fall colonies. Figure 4 below shows loss of individuals. The loss of a single colony (by 41 individuals) represents 45.5% of total individuals reporting loss. Four individuals (4.5%) lost seven or more colonies. The highest loss by a single beekeeper was 14 colonies. Loss numbers are reflective of the fact that the median number of bee colonies of backyarders was four colonies. Of 200 colonies lost in Oregon, individuals with 1, 2 or 3 colonies lost 57 colonies, 34%; individuals with 4 to 6 colonies (216 total colonies) lost 22%. Individuals with six or fewer colonies lost 27.5% of their colonies. The 39 individuals with 7 or more colonies lost 36.5% of their colonies while individuals with 10+ colony numbers lost ½ that level – 14.5% of their colonies. 

The 20 Individuals who had 12 to 41 colonies lost 57 total colonies. These individuals lost anywhere from 1 to 12 colonies; 8 individuals with 12 or more colonies lost no colonies. This group lost a one-quarter fewer colonies (15%) than the overall statewide group (20%) and slightly less than ½ of individuals with 1-3 colonies (34% loss average).

 Survey respondents are primarily small colony number beekeepers – 47% had 1-3 colonies but they vary considerably in their years of beekeeping experience. Looking at losses by colony holding numbers, the 81 individuals who had 1-3 colonies had 34% loss level, the 46 individuals with 4-6 fall colonies (27% of individuals) had a 22% loss level, the 19 individuals with 7-9 fall colonies (20% of individuals) had a 14% loss level and the 20 individuals with 10+ colonies (12% of respondents) lost 21% of their colonies. Numbers are close to those of last year.

By years of experience, the 56 individuals who had 1 to 3 years bee experience (33% of total respondents)  had 27% colony loss level and the 49 individuals with 4-6 years experience (29% of 

survey takers) had a  19% loss level. Individuals with 6 or fewer years experience, 60% of total respondent number, had 22% loss level. The 27 individuals with 7-9 years experience (16% of respondents) had a 14.5% loss level and those 40 individuals (23% of respondents) with 10+ years experience had a 20.5% loss level. Thus the 40% of survey respondents with 7 or more years experience had an 18.5% loss level. As colony numbers or years experience increase the percent loss level decreases.

Overwinter Losses the Past 14 Seasons

Comparison of the annual losses of backyarders with commercials is shown in Figure 7. The commercial losses are obtained from a different paper survey distributed by Oregon State University. The numbers for the current year are early returns of 4 commercial and 3 sideliner beekeepers (total colony number fall=13,538 and 3 sideliner beekeepers (449 colonies). Commercial loss rate is 23.5 and sideliner is 16. Fifteen-year average Backyard losses =36.7% loss and 15-year commercial/semi-commercial loss = 21.7%. The Bee Informed average=23.7.   

Some Other Numbers

Twenty-five individuals (15%) had more than a single apiary location. The loss level at 2nd apiary was higher in seven instances but also was lower at the original site in the same number of instances.  Seventy-seven percent (77%) of respondents (3% above last year) said they had a mentor available as they were learning beekeeping. Fifty-four individuals (31%) had more than one hive type. And, finally, 10 individuals (6%) moved their bees. One move was sale/gifting of hives, one was due to owner move, one was due to conflict with neighbor, two were for better site, one move was due to bear attack and four were for pollination of crops.  Distances were within the same property up to miles away (for relocation and pollination).  

Perceived Colony Death Reason and Acceptable Level

The survey asked individuals that had colony loss (81 individuals had no loss) to estimate what the reason might have been for their loss (multiple responses were permitted). There were 167 total listings, 1.85/individual. Queen issues (38), weak in the fall (31) and varroa (30 individuals) were most common.  Starvation, 16 selections and yellow jackets, 11 respondent choices, along with don’t know (12 selections) were 3 additional double-digit choices. Among others one indicated extreme cold and rain, another cited lack of attention, one said pigs knocked hives over and another that wind blew cover off exposing the bees. See Figure 6 graph below. 

Acceptable loss: Survey respondents were asked the reason for loss. Twenty-three (14%) indicated zero (no loss). Thirty-eight percent of individuals indicated 15% or less; 20% was medium choice, as has been the case for several years. The most common response was 25%. Thirteen percent said 50% or greater was an acceptable loss level; one said 75 and 2 said 100% loss levels acceptable. See table below.  

Why do colonies die?

There is no easy way to verify reason(s) for colony loss. Colonies in the same apiary may die for several reasons. Examination of dead colonies is at best confusing and, although some options may be ruled out, we are often left with two or more possible reasons for losses. A dead colony necropsy can be of use. Opinions vary as to what might be an acceptable loss level. We are dealing with living animals which are constantly exposed to many different challenges, both in the natural environment and the beekeeper’s apiary. Individual choices varied from zero to 100%, with a medium of 20%. 

The major factor in colony loss is thought to be mites and their enhancement of viruses especially DWV (deformed wing virus), VDV (Varroa destructor Virus (also termed DWV B) and Israeli and chronic paralysis virus. But we do not have a test for these viruses. It was interesting in that queen problems were the most frequently indicated as were weak in the fall as leading reasons for loss.

Declining nutritional adequacy/forage and diseases, especially at certain apiary sites, are additional factors resulting in poor bee health. Yellow jacket predation is a constant danger to weaker fall colonies. Management, especially learning proper bee care in the first years of beekeeping, remains a factor in losses. What affects our changing environment such as global warming, contrails, electromagnetic forces, including human disruption of them, human alteration to the bee’s natural environment and other factors that play in colony losses are not at all clear. 

There is no simple answer to explain the levels of current losses nor is it possible to demonstrate that they are necessarily excessive for all the issues our honey bees face in the environment. It was encouraging to see from survey responses that losses this past year 30% were still at a low level. More attention to colony strength and possibility of mitigating winter starvation will help reduce some of the losses. Effectively controlling varroa mites will help reduce losses.

Colony Managements

We asked in the survey for information about some management practiced by respondents. The survey inquired about feeding practices, wintering preparations, sanitation measures utilized, screen bottom board usage, mite monitoring, both non-chemical and chemical mite control techniques and queens. Respondents could select multiple options and there was always a none and other selection possible. This analysis seeks to compare responses of this past season to previous survey years. 

TO BE CONTINUED: It will take longer to do this analysis. Results will be posted as soon as possible. 

Closing comments

This survey was originally designed to ‘ground truth’ the larger, national Bee Informed loss survey.  See statewide PNW reports for OR and WA for this comparison (graph 5 in this report). The numbers while slightly different do in fact track well. Unfortunately, the national BIP survey was discontinued after 2023. See the BeeInformed website www.beeinformed.org for additional information and to examine that data base as well. The BeeInformed survey is measuring the larger scale OR beekeepers not the backyarders as loss rates are of total colony number. Reports for individual bee groups are customized and only available from the PNW website; they are posted for previous years. 

I intend to continue to refine this instrument each season and hope you will join in response next April.  If you would like a reminder when the survey is open please email us at info@pnwhoneybeesurvey.com with “REMINDER” in the subject line. I have a blog on the pnwhoneybeesurvey.com and will respond to any questions or concerns you might have. Email me directly for a quicker response. dmcaron@udel.edu 

Thank You to all who participated.  If you find any of this information of value please consider adding your voice to the survey in a subsequent season.      Dewey Caron May  2024


Winter Bee Losses of Washington Backyard Beekeepers for 2023-2024

by Dewey M. Caron

Click here to view a PDF of Washington report.

Overwintering losses of small-scale Washington backyard beekeepers=31%, a decrease of five percentage points from last year, 14 percentage points below the 9-year loss average. One hundred twenty-one Washington respondents completed a survey, one more than last year and two above the 119 average respondent rate of the last five years. Information on winter losses and several managements related to bee health was included on the electronic honey bee survey instrument www.pnwhoneybeesurvey.com

Response by local Washington (WA) association members varied as indicated by numbers adjacent to club name. Losses of those club individuals are shown in blue bars in Figure 1. Statewide loss level was 31%. Survey included 693 fall Washington beekeeper colonies (4 more than last year)  

2023-2024 Overwinter Losses by Hive Type 

The Washington survey overwintering loss statistic was developed by subtracting the number of spring surviving colonies from fall colony number supplied by respondents by hive type. Results, shown in Figure 2 bar graph, illustrate overwintering losses of 121 total WA beekeeper respondents =31%. Langstroth 8 frame beehives had higher average losses (37%) than Langstroth 10 frames hives. Only two nucs of 18 in the fall failed to survive. Top Bar hive survival rate was similar to the Langstroth hives. One of two Warré hives survived. Of the 18 individuals listing another hive type, 9 were IDed as AZ (only 1/3rd survived), 4 as Layens (all survived) and 13 as long hives (9 survived =31% Loss). The remaining 21 were not identified. (NOTE: Hive type of 47 Fall colonies not captured).

  Forty-six individuals had no loss (38%) = 217 colonies while ½ that number (22) 18% had total loss = 68 colonies. Greatest loss was one colony. Heaviest loss was 14 colonies. See Figure 3 graph. 

The WA respondents to the electronic survey managed up to 26 fall colonies. Fourteen individuals had a single colony (and had colony loss of 43%), 30 respondents had two colonies (the greatest number) with 33% loss and seven individuals had three colonies (48% loss). Typical of previous surveys, fifty-one individuals (42% of respondents) had 1, 2 or 3 fall colonies (loss level of 41%). Thirty-five individuals had 4 to 6 fall colonies and had a loss level of 43%. Five was the median number. Eighteen individuals had 7 to 9 colonies, they had a loss level of 19%. Ten individuals had 10-19 colonies with a loss level of 30%, 6 individuals with 20-26 colonies had a loss level of 23% The 16 individuals with 10+ colonies lost 27%. 

Thirty-six respondents (31% of total) had 1, 2 or 3 years of experience; they had a 30% loss level; the 12 individuals with one year experience had the heaviest loss of 38%. Forty-two individuals (36% of total respondents) had 4 – 6 years’ experience (medium number = 5 years experience) with a 42% loss, 14 individuals had 7-9 years experience (loss level 41%), 17 had 10-19 years keeping bees and 18% loss level and nine had 20+ years experience (64 was maximum) and they had a 26% loss level. Examining the relationship of colony numbers and years experience related to loss shows that loss of colonies decreases by about 1/3rd with the greater number of colonies and/or years of experience.

Summary

1-3 colonies     41% loss 10+ colonies     27% loss

1-3 years experience        30% loss 10+ years experience      20% loss    

Eighty-eight (75%) WA beekeepers had an experienced beekeeping mentor available as they were learning beekeeping. This percentage was three percentage points higher than last year, the same as the 5-year average.  

Survival Based on Hive Origination

We also asked about hive loss by origination. Data shown in Figure 4 below. Best survival was Splits/divides (15%) with swarms and previously overwintered both at 16% loss rate. previously overwintered colonies and splits/divides. Package bee losses were over 50%. Both nucs 40% and packages had heaviest losses. 

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Comparison to Larger-Scale Beekeeper Losses

A different (paper) survey instrument was mailed to Pacific Northwest (PNW) semi-commercial (50-500 colonies) and commercial beekeepers (500+) from OSU asking about their overwintering losses. Response rate was reasonable until 2018 then the response became limited to only three individuals and this was not considered representative of the larger scale beekeepers of Washington. Numbers are shown in red only for the 4 years 2015-2018 in Figure 5 below.  The BeeInformed.org (BIP) losses for Washington beekeepers for 2015 to 2023, the last year of the BIP survey, are representative of the larger scale beekeepers and are shown in blue in Figure 7. Losses of backyard beekeepers from this survey are shown in orange line with black loss numbers. Average BIP loss (9 years) =27.9% and average WA backyarder loss (10 years) =44.7%. In 2023 the larger-scale beekeeper loss exceeded losses of backyarders. The numbers included in the survey are shown below the figure.

The reasons backyarders have had higher losses are several. Commercial and semi-commercial beekeepers examine colonies more frequently and they examine them first thing in the spring as they move virtually all their colonies to pollinate almonds in February. They also are more likely to take losses in the fall and are more proactive in varroa mite control management.

The PNW survey was conducted in part to “ground truth” the annual BeeInformed Survey (BIP) also conducted during April. The BIP survey includes a mailed survey to larger-scale beekeepers and an electronic survey to which any Washington beekeeper can submit their data. Losses reported include colonies of migratory beekeepers who reported WA as one of their yearly locations. The BIP survey for the 2015-23 annual surveys reports receiving responses from 90 to 95% of respondents exclusive to Washington but they managed less than 5% of total colony count – the BIP tally is primarily of commercial beekeepers.  They have large numbers of colonies in survey data, so the BIP losses reflect commercial losses not losses of backyarders. See https://research.beeinformed.org/loss-map/ 

Apiary sites and moves

Nine survey respondents had bees at more than a single apiary. Loss levels were similar or better at four of the original sites and better at five of the 2nd sites. Three had bees at a third site and losses were higher at two of the 3rd sites. Six individuals moved bees. One moved for pollination, one moved for construction, two moved due to bear attack and two moved for better site (more sun, lower elevation for wintering). 

Colony death perceived reason and acceptable loss level 

We asked survey takers who had winter losses for the “reason” for their losses. More than one selection could be chosen. In all there were 115 WA selections (1.85/individual) provided. Varroa mites (32 individuals, 25% of total selections) were the most common choices. Weak in the fall, starvation and poor wintering were next most common followed by yellow jackets and don’t know. Ten individuals only listed queen issues. The two “other” listings were absconding and too small a winter cluster. Figure below shows the number and percent of factor selections. 

Acceptable loss: Survey respondents were asked the reason for loss. Seventeen (15%) indicated zero (no loss). Thirty-three percent of individuals indicated 10% or less. Twenty percent was a medium choice. Nineteen percent said 50% was an acceptable loss level. See table below. 

Why do colonies die?

There is no easy way to verify reason(s) for colony loss. Colonies in the same apiary may die for several reasons. Examination of dead colonies is at best confusing and, although some options may be ruled out, we are often left with two or more possible reasons for losses. A dead colony necropsy can be of use. Opinions vary as to what might be an acceptable loss level. We are dealing with living animals which are constantly exposed to many different challenges, both in the natural environment and the beekeeper’s apiary. Individual choices varied from zero to 100%, with a medium of 20%. 

Major factors in colony loss are thought to be mites and their enhancement of viruses especially DWV (deformed wing virus), VDV (Varroa destructor Virus (also termed DWV B) and Israeli and chronic paralysis virus. But we do not have a test for these viruses. It was interesting in that queen problems were the most frequently indicated as were weak in the fall as leading reasons for loss. 

Declining nutritional adequacy/forage and diseases, especially at certain apiary sites, are additional factors resulting in poor bee health. Yellow jacket predation is a constant danger to weaker fall colonies. Management, especially learning proper bee care in the first years of beekeeping, remains a factor in losses. What affects our changing environment such as global warming, contrails, electromagnetic forces, including human disruption of them, human alteration to the bee’s natural environment and other factors that play in colony losses are not at all clear. 

There is no simple answer to explain the levels of current losses nor is it possible to demonstrate that they are necessarily excessive for all the issues our honey bees face in the environment. It was encouraging to see from survey responses that losses this past year 30% were still at a low level. More attention to colony strength and possibility of mitigating winter starvation will help reduce some of the losses. Effectively controlling varroa mites will help reduce losses.

Colony Managements

We asked in the survey for information about some management practiced by respondents. The survey inquired about feeding practices, wintering preparations, sanitation measures utilized, screen bottom board usage, mite monitoring, both non-chemical and chemical mite control techniques and queens. Respondents could select multiple options and there was always a none and other selection possible. This analysis seeks to compare responses of this past season to previous survey years. 

TO BE CONTINUED: It will take longer to do this analysis. Results will be posted as soon as possible. 

Closing comments

This survey was originally designed to ‘ground truth’ the larger, national Bee Informed loss survey.  See statewide PNW reports for WA for this comparison (figure 5). The numbers while slightly different do in fact track well. Unfortunately, the national BIP survey was discontinued after 2023. See the BeeInformed website www.beeinformed.org for additional information and to examine that data base as well. The BeeInformed survey is measuring the larger scale WA beekeepers not the backyarders as loss rates are of total colony number. I have discontinued recording WA commercial/ sideliner numbers as I receive too few responses to be representative of them. Reports for individual bee groups are customized and only available from the PNW website; they are posted for previous years. 

I intend to continue to refine this instrument each season and hope you will join in response next April.  If you would like a reminder when the survey is open please email us at info@pnwhoneybeesurvey.com with “REMINDER” in the subject line. I have a blog on the pnwhoneybeesurvey.com and will respond to any questions or concerns you might have. Email me directly for a quicker response. dmcaron@udel.edu 

Thank You to all who participated.  If you find any of this information of value please consider adding your voice to the survey in a subsequent season.                Dewey Caron May  2024