Winter Bee Losses of Oregon Backyard Beekeepers, 2017-2018
by Dewey M. Caron and Jenai Fitzpatrick
Overwintering losses of small scale Oregon backyarder beekeepers were reduced this past winter compared with the 2016-17 previous season. The reason(s) for colony losses is not always obvious as there often are several contributing factors. Herein we review and discuss the data provided by 303 Oregon smaller-scale beekeepers (20 more than last year), in an effort to weigh the loss impact factors.
This report presents the results of a 10th season of loss surveys of small-scale Oregon (hobbyist) backyard beekeepers and the 5th season of the expanded digital version. This annual survey is conducted electronically during April and supplemented with paper surveys distributed at several late-March and April local association meetings. In all, 407 valid surveys were returned, 303 from Oregon and 104 from Washington beekeepers.
Characterization of survey respondents
Surveys were received from members of 14 local Oregon (OR) associations and several Washington associations. The majority of the OR respondents (225= 74%) keep bees in the Willamette Valley of Oregon.
Additional surveys were received from 20 Coastal beekeepers (10 from Tillamook beekeepers), 13 from Hood River, 16 from Central OR and 20 from Southern Oregon beekeepers. The majority (80=77%) of Washington responses were from beekeepers in the I-5 corridor Vancouver to Tacoma area. In bar graph, the number beside club name shows club respondent numbers and percent figure at end of bar represents the loss level percent of each association. See Figure 1.
We asked if there was a mentor available for the first years of beekeeping. 69% Oregon beekeepers indicated YES. This is encouraging as the learning curve is a steep one for new beekeepers and mentors can significantly help new individuals get through the critical 1st / early years.
To better characterize the respondent population, we asked how many years of beekeeping experience survey respondents had. The medium years of beekeeping experience was 4 years with 42.5% of respondents having 1, 2 or 3 years of experience; 95 individuals (32%) had 4 or 5 years experience. Forty individuals (13%) had ten years or more of experience with 8 individuals listing 30 or more years of experience; the greatest was 50 years.
2017-2018 Overwinter losses (based on hive type)
The loss statistic was developed by asking number of fall colonies and number in the spring by hive type. Total Oregon backyard beekeeper overwinter loss = 38%. Results are shown in bar graph of Figure 4. Number of fall (1277 colonies) and spring hives (789 surviving colonies) are shown by hive types. Eight-nine percent (89%) of hives were 8 and 10 frame Langstroth hives. Fifty four individuals (19%) maintained more than one hive type.
The 36% winter losses of PNW 8-frame Langstroth hives, was 3 percentage points lower than the 39% loss rate of 10-frame Langstroth hives, but not statistically different. There has been no statistical difference in 3 of 4 years in loss percent between 8 and 10 frame hives; nuc losses are often higher but were a bit lower this past winter. Top bar hive and Warré losses both were higher, 53% and 45% respectively. Of the 35 “other” hive types, 6 were long hives (all survived), 2 flow hives (neither survived), 5 tree hives (of which 3 survived), 4 insulated hives (only 1 survived); the remainder not identified.
The 104 Washington beekeepers, entering the fall with 457 colonies had a slightly higher loss rate of 44%. The reason(s) for higher losses by Washington beekeepers the past three years are unknown but the lower number of Washington respondents compared to Oregon could be partly responsible. Small numbers, such as with individual clubs, are more difficult to interpret; one or two returns can skew results.
Thirty-five percent (34%) of OR respondents (91 individuals) had NO LOSS overwinter, whereas 22.5% (59 individuals) lost 100% of fall colonies. Sixty nine individuals lost 1 colony, 45 individuals lost two, 19 of respondents lost 3 colonies and 18 lost 4 colonies. Fourteen individuals lost 6 to 9 colonies and 5 individuals (all who had 10+ fall colonies) lost 10 or more colonies – highest loss was 18 colonies. Numbers are reflective of the fact that backyarders keep on average 3 colonies.
There were 25 beekeepers (9.5%) who had more than 25 colonies. Three of these individuals (12%) lost no colonies, 2 each lost one or two colonies, 3 each lost 3 and 4 colonies, 4 lost 5-9 colonies and 5 lost 10 or more colonies. Figure 3a. These individuals tended to have more beekeeping experience. Nine had 3 to 5 years experience, 8 had 6-8 years, 3 had 10 to 17 years and 7 had 20 to 50 years experience.
Loss rates at different locations
We asked loss related to location of the hive. Eighty-eight percent of respondents kept bees at a single location. Of those, 34 individuals had two locations, 11 had 3 and 3 had 4 apiary locations. Loss numbers were higher at 2nd/3rd apiary sites (33% loss compared to 28% at the primary location) Information supplied on location will be used to develop location density maps similar to maps prepared by Jenai in 2014.
Overwinter losses of members of different organizations are shown in the Figure 1 above. The loss rates varied from a low of 10% for the Southern Oregon beekeeper respondents to a high of 55% in PUB Association. The range of losses, 4 and a half difference was the highest of last three years; last year there was a 2-fold difference (34 to 70% loss rates) while the previous year range was 20%to 80%, a 4-fold difference. Bar length of Figure 1 is expression of percent loss.
Twenty five individuals (9%) moved colonies during the year. Reasons listed for move included 7 individuals who moved anywhere from a few yards to several feet to improve hive siting, 4 individuals who moved for better forage conditions, 5 moved a hive as gift from or to give to friend/family and 2 who moved bees for pollination. One had to move from bear predation, another to escape high hive numbers of commercial neighbor and another because there were too many colonies for the city regulations. One indicated moving hives to avoid pesticide damage, another lost the apiary site and one moved as they lost interest.
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+) asking about their overwintering losses. Seven Oregon commercial and six semi-commercial beekeepers (36,801 colonies, approximately 50% of the estimated total number of colonies in the state) reported overwinter losses of 15%. Small scale beekeeper losses were one percentage point less than the average of the 3 previous years while commercial/semi-commercial losses were 3 percentage points less than the average of the previous three years. Both group loss rates were 10 percentage points lower than the previous winter. Comparisons of losses for the last 4 years are shown in Figure 4.
Backyard losses, slightly more than double the losses of larger-scale beekeepers, have consistently been higher over 7 years of survey responses. Commercial and semi-commercial beekeepers take losses in the fall and are more pro-active in varroa mite control management are two possible reasons for this difference.
Survival based on hive origination
We also asked survey respondents to characterize their loss by hive origination. The result is graphically presented below in Figure 5. There was relatively little difference but as expected overwintered colonies had the best survival (41% loss) and feral hives (59% loss) and packages (52% loss) did the poorest. Splits (34%) and swarm survival (44% loss) did slightly better.
Colony Death perceived reason and acceptable level
We asked PNW individuals that had colony loss for their expression of what might have been the reason for their loss. More than one option was allowed for those with multiple losses. Most common responses were Varroa mites (23%) and Queen failure (17%), followed closely by Weak in the Fall (14%).Poor wintering conditions (10%) and Yellow jackets (6%) were other common selections. CCD (Colony Collapse Disorder) 4%, a general loss symptom whereby the adults die away from their hive, Pesticides (3%) and starvation (5%) were other selections. No opinion was expressed by 3%.
There is no easy way to verify reason(s) for colony loss. Colonies in the same apiary may die for different reasons. Doing the dead colony examination (necropsy) is the first step in seeking to solve the heavy loss problem. More attention to colony strength and possibility of mitigating winter starvation will help reduce some of the losses. Effectively controlling varroa mites will definitely help reduce losses.
Acceptable loss: Respondents were asked to select an acceptable loss level, being offered several categories to check. Sixty-five individuals (21%) said zero, the most common selection; the medium (middle selection) was 15%. Nationally, the Bee Informed survey response to the same question has been between 15 and 19%: this past year it was 15%. OR data shown in Figure 6.
Why do colonies die? There appears to be no single reason for loss and a good deal of variance in opinion as to what might be an acceptable loss level. There is nobody to come check why a dead colony died. Close examination may eliminate some possible factors but we are still often left with more than one “likely” cause of death. Nationally the BIP data base indicates that about 1/3 of individuals have no loss or very low losses, about a 1/3 have losses around the average figures for the year while the 1/3rd with heaviest losses tend to be individuals who are not doing, or perhaps not properly doing, varroa mite control.
We are dealing with living animals which are constantly exposed to many different challenges, both in the natural environment and the beekeeper’s apiary. The four major factors in colony loss are thought to be mites, pesticides, declining nutrition adequacy of the environment and diseases, especially viruses and Nosema. Management, failure to do something or doing things incorrectly, remains a factor in our losses as does alteration to the bee’s natural environment.
Langstroth wrote about the importance of taking losses in fall management saying if the beekeeper neglects such attention to his/her colonies, 45% loss levels may occur, depending upon variable environmental conditions. It can be argued that losses of 30% or more might be “normal.” Older, more experienced beekeepers recall when loss levels were 15% or less. Honey production fluctuates each year but, once again, seems to be declining on average. Numbers of U.S. bee colonies have declined steadily since the 1940s, returning to numbers of 100 years ago; worldwide numbers of bee colonies are steadily increasing.
There is no simple answer to explain the levels of current losses nor is it possible to demonstrate that they are excessive for all the issues facing honey bees in the current environment.
PART 2; General hive practices and losses
We asked in the survey for information about some managements practiced by respondents. Multiple responses were possible. Analysis will take longer and will be available on website as soon as completed.
Washington backyard beekeeper Winter Losses 2017-18 Dewey Caron
One hundred four Washington beekeepers supplied information on winter losses and several managements related to bee health with an online honey bee survey. Overwintering losses of small scale Washington beekeepers was reduced from the previous elevated loss levels in 2016-2017.
Figure 1 shows total Oregon (OR) and Washington (WA) response by local association. Statewide loss level is highlighted. Number individuals ( ) to left of association name is number of repondents, bar length is % overwinter losses by club. Total fall colony response was 303 OR and 104 WA individuals; survey includes 1277 OR colonies (789 surviving = 38% loss) and 457 WA colonies (256 surviving = 44% loss).
The Washington respondents to the electronic survey were a mixture of single digit colony numbers and others with more colonies and of new beekeepers mixed with more experienced individuals. Thirty seven percent (37%) of WA respondents had 1 or 2 years of experience; 28% had 3 to 4 years’ experience (medium number = 3). 10 individuals (12%) had 5 to 7 years, 10% had 7 to 10 years and 12% had 14+ years of experience, [40% above 30 years]; highest was 55. For fall colony numbers, 40.5% had 1 to 2 colonies, 26% had 3 or 4 colonies (medium was 3 colonies/individual), 19% had 5, 6 or 7 colonies, 8% had 8, 9 or 10 colonies and 7% had 12+ colonies; largest number was 35 colonies. Of the last 7% (>12 year’s experience) there was 17.5% average years of experience and average of 6 colonies lost/individual.
Seventy one (73%) of WA beekeepers had an experienced beekeeper mentor available as they were learning beekeeping. This percentage was up from 62% the previous year.
2017-2018 Overwinter Bee Losses
Total WA backyard beekeeper overwinter loss = 44% loss.
The WA survey overwintering loss statistic was developed by our asking number of fall colonies and surviving number in the spring by hive type. Results, shown in Figure 2 bar graph, illustrates overwintering losses for 104 total WA beekeeper respondents. Langstroth 8 and 10 frame beehives (88% of total) had heavier losses than 5 frame nucs (40% loss) and alternative hives. Other hive types Identified included long hives, tree hive and skeps plus others not specifically identified. The previous year overall WA colony loss was 63%.
Origination: We also asked about hive loss by origination. Data shown in Figure 3. Overwintered and swarms had better winter survival than did packages, nucs and splits. Feral colonies exhibited the best survival rate, although fewest in number.
Among 101 total WA beekeepers (4 individuals were new beekeepers), 15 individuals (15%) maintained more than one hive type. For the total WA beekeepers, 27 (27%) had no loss and 23 individuals (23%) had total loss. Twenty-nine WA individuals lost 1 colony, 21 individuals lost 2 colonies and 10 individuals lost 3 colonies (60% of individuals with losses). Seven (7) individuals lost 12 or more colonies; highest loss was 20 colonies. Data in Figure 4.
Comparison of backyarders and commercial/semi-commercial beekeepers
A different (paper) survey instrument was mailed to Pacific Northwest (PNW) semi-commercial (50-500 colonies) and commercial beekeepers (500+) asking about their overwintering losses. Comparison is shown in Figure 5 below with approximate number of colonies represented by the commercial/semi-commercial beekeepers and number of individual backyarder survey respondents.
Backyard losses have consistently been higher, most years double the losses of larger-scale beekeepers. The reasons for this dichotomy are complex. Commercial and semi-commercial beekeepers examine colonies more frequently and they examine them first thing in the spring as they take virtually all of their colonies to Almonds in February. They also are more likely to take losses in the fall and are more pro-active in varroa mite control management.
Self-reported “reasons” for colony losses: 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 156 WA selections (1.5/individual) provided. Weak in the fall (21 individual choices), poor wintering conditions (19 choices), Varroa mites (18 individuals) and queen failure (21 individuals) were the major factors listed, closely followed by don’t know (16 individuals). The side bar shows other selections.
There is no easy way to verify reason(s) for colony loss. Colonies in the same apiary may die for different reasons. Doing the dead colony examination (necropsy) is the first step in seeking to solve the continuing heavy loss problem. More attention to colony strength and checking stores to help avoid winter starvation will help reduce some of the losses. Control of varroa mites will also help reduce losses.
Respondents were asked to select an acceptable loss level, being offered several categories to check. Four individuals said zero, while 8 said 10% ((25% for both responses) 19 said 25% (40%), 5 said 33% and 9 said 50% loss (19%) was acceptable. One individual each said 75% and 100% (4%).
Why do colonies die? There appears to be no single reason for loss and a good deal of variance in opinion 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. Major factors are thought to be mites, pesticides, declining nutrition adequacy of the environment and diseases, especially viruses and Nosema. Management, failure to do something or doing things incorrectly, remains a factor in our losses.
What effects our alteration to the bee’s natural environment and other external factors play in colony losses are not at all clear.
Langstroth wrote about the importance of taking winter losses in fall management saying if the beekeeper neglects such attention to his/her colonies 45% loss levels may occur, depending upon variable environmental conditions. It can be argued that losses of 30, 40, 50% or more might be the new “normal.” Older, more experienced beekeepers recall when loss levels were 15% or less. Honey production fluctuates each year but, once again, seem to be declining on average. Numbers of U.S. bee colonies have declined since the 1940s, returning to numbers for 100 years ago, although numbers for the last 3 decades have not changed. Worldwide numbers of bee colonies are steadily increasing.
So there is no simple answer to explain the levels of current losses nor is it possible to demonstrate that they are excessive for all the issues facing honey bees in the current environment.
Pro-active Managements: Do you feed bee colonies in your care with sugar, honey or protein? Do you take extra measures for wintering preparation? Are we doing the sanitary practices we would in animal husbandry with our bees such as cleaning hive tools/frequently washing gloves (if used) between inspecting different hives or, when we find it necessary to take a frame from one colony to another do you check to confirm the donor colony is healthy?
Part 2 of the loss survey asks some basic questions to allow comparison of loss rates from beekeepers who may perform one management with those who don’t do that management or with the average loss level. This analysis takes longer to complete. It will be posted as soon as available.
THANK YOU. Bee counted-Bee informed! I hope you find this useful. Please consider participating in the PNW and/or the National BIP survey next April! Help make the Washington state report more robust with an even larger participant base next year.
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