** Looking for a report in your specific region? Refer to the Individual Club Reports page.
** Scroll down to see the (COMING SOON) Washington Backyard Beekeepers Winter Bee Loss Report, 2020-21 or click here to view Washington as PDF.
Winter Bee Losses of Oregon Backyard Beekeepers for 2020-2021
by Dewey M. Caron and Jenai Fitzpatrick
Click here to view a PDF of Oregon report.
Overwintering losses of small-scale Oregon backyard beekeepers decreased to 35% this winter after the disastrous level of 48% colony losses two years ago and 38% last winter. This report presents the results of our 12th season of Oregon hobbyist/backyard beekeeper surveys. This annual survey is conducted at www.pnwhoneybeesurvey.com. Herein we discuss the data provided by 328 Oregon beekeepers, which is 26 more respondents than last year. Results of the 163 Washington respondents completing surveys (30 more than last year) are included in a separate loss report.
2020/2021 State/Club Losses
Club results of 12 local Oregon associations and 6 Washington associations (+ “other” category) are shown in Figure 1. Colony numbers ranged from 1 to 40 colonies in Oregon (Average 4.77 colonies, medium number = 3 colonies) and 1 to 39 in Washington (Average 5.16 colonies, Median number = 3). The number of respondent individuals is 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 27% for the Tualatin Valley beekeeper respondents to a high of 55% for Columbia Association. The 2X range of losses, was less than last year (4X difference) or the year before (3X difference). The difference between the two states – 2 percentage point higher loss rate in Washington – is the closest it has been in several survey years (last year Oregon loss rate was 38% and Washington loss rate was 50%). The 11 “OR-other” includes beekeepers In Coos Co, South coastal range, Douglas Co, + 6 in Klamath Falls area. The 24 “WA-other” includes beekeepers mostly west of the Cascade Range. The Puget sound east are beekeepers mostly in the Seattle area. Three quarters of our Pacific Northwest Honeybee Survey respondents keep bees along the I-5 corridor between Eugene and Seattle.
2020-2021 Overwinter Losses by Hive Type
The loss statistic was developed by asking number of fall colonies and surviving number in the spring by hive type. Respondents had 1,564 fall colonies (211 more than last year) of which 1012 colonies survived to spring equating to a 35% loss (or 65% survival), an improvement of 3% points over the previous winter (38%) loss rate. Eighty-seven percent of hives were 8-frame and 10-frame Langstroth hives which had a survival rate of 65%. There were 74 fall nucs (68% survival rate). Among non-traditional hive types were 45 top bar hives (44% survived) and19 Warré hives (51% survived). Among other hive types, 48 were horizontal hives (moveable comb) and up to 16 (not all other hive types were Identified) that included tree stump and other non-traditional hive types. Thus, at most, 80 (5%) of hives were non-traditional Langstroth hives.
The 30% winter losses of PNW 8-frame Langstroth hives was slightly less compared to the 37% loss rate of 10-frame Langstroth hives. The loss rates of Langstroth 8 and 10 frame hives over the past 7 years has averaged 37% for 8 frame Langstroth hives and 40% loss for 10 frame hives respectively. Nuc losses are typically higher than losses of 8 or 10 frame Langstroth hives but this year came in at 32% loss. The Nuc 6-year average loss is of 50%. This year’s Top Bar hive loss (56%) is only 2 % points over the 6-year average loss of 54%. The 2021 Warré hive loss rate of 47% is a higher loss than the 6-year average of 40%. Although many beekeepers come and go, it is interesting that each survey year Top Bar and Warré hives numbers remain steady at slightly over 5% of total hives.
2020-2021 Loses Based on Hive Origination
We also asked survey respondents to characterize their loss by hive origination. The result is graphically presented below in Figure 3. Overwintered colonies obviously had the best survival (28%) with the 29 feral transfers also excellent. Splits, swarms and nucs were higher with package bee survivals exhibiting double the losses of the overwintered colonies.
2020/2021 Individual Hive Losses
Thirty percent 98 individuals) of Oregon respondents had NO LOSS overwinter, whereas 21% (69 individuals) lost 100% of fall colonies. Figure 4 below shows loss of 1, 2, 3, 4 and 5 colonies; the loss of 1 single colony (by 132 individuals) represents 57% of total individuals reporting loss. Nineteen individuals lost 6 or more colonies. Highest loss by a single beekeeper was 17 colonies. Loss numbers are reflective of the fact that backyarders keep on average 3 colonies. Those individuals losing 1, 2 or 3 colonies lost 53% of total colony loss statewide this past winter.
Graph 5 looks at losses of individuals who had 10 to 40 colonies. This group lost 175 total colonies which is 28% of total losses. Thus individuals with 10 to 40 colonies (Averge colony number=15) lost 4.7 colonies per individual and a smaller percentage of colonies (28%) than the overall group (35%). Indivdiuals with 1 to 9 colonies lost 1.6 colonies on average.
Overwinter Losses the Past 12 Seasons
The losses of the past 12 years are graphed below in Figure 6. Despite the lower losses the past 2 seasons the average loss by Oregon beekeepers is 40%. This average loss has changed little in the past 12 years although season with heavier loses have occurred. Comparing 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. Four Oregon commercial and six semi-commercial beekeepers (26,175 colonies, approximately 30% of the estimated total number of colonies in the state) reported overwinter losses of 24%. Interestingly this year losses of the six semi-commercial (sideliner) beekeepers (average colony number 164) were 21% and losses of the commercial beekeepers (average colony number 6298) were slightly higher, 24%. The normal progression is commercial loses lowest followed by sideliner then small-scale beekeepers with 10+ colonies (this year 28% figure 5) and finally the backyard beekeepers with heaviest losses. Small scale (backyard) beekeeper losses have ranged from six to 20 percentage points greater compared to losses of commercial/semi-commercial beekeepers over the last 12 years as shown in Figure 7. Twelve-year average Backyard=40% loss and 12-year commercial/semi-commercial loss = 21%. The dashed lines are loss trend.
Who are Survey Respondents?
To better characterize the survey population, we tallied individual number of fall colonies for the 328 respondents. As indicated in the blue bar of Figure 8. Fifty-six individuals had 1 colony, 75 had 2 colonies (the most common colony number), 62 individuals had 3 colonies (the middle number), etc. 37 individuals (11% of individuals) had 10+ colonies. Highest colony number was 40.
We also asked how many years of beekeeping experience survey respondents had as indicated by the red bars of Figure 8. Thirty-nine had 1 year, 33 had 2 years, 38 had three years which was just over 1/3rd of total respondents. The greatest number was 5 years (44 years’ experience, which was also the middle number years of beekeeping experience). On other end of spectrum, 63 individuals (19%) had 10+ years’ experience. 62 years’ experience was the highest.
Nearly three quarters of Oregon beekeeper respondents (71%) indicated they had a mentor available for the first years of beekeeping. This is about same as in previous years. 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 early years of keeping bees.
Perceived Colony Death Reason and Acceptable Level
We asked individuals that had colony loss (98 individuals had no loss) to estimate what the reason might have been for their loss (multiple responses were permitted). There were 445 total listings, 1.86/individual. Varroa (111 selected -46% of respondent choices), followed by Weak in the fall (82 chose 34%), Queen Failure (69 selected 29%), starvation and poor wintering (both 31 choices 13%) were most commonly checked. 40 individuals chose Don’t know (17%). Among other, 17 individuals listed yellow jackets, 12 fire/smoke, 11 pesticides, 9 moisture and 7 CCD. Other reasons written in under other included beekeeping error, small hive beetle, ants, mice, swarming, absconding and late colony hiving.
|Varroa mites||Queen failure||Weak in fall||Star-vation||Yellow jackets||Pest-icides||Don’t know||Other|
|Loss (#) reason (%)||111 (46%)||69 (29%)||82 (34%)||31 (13%)||17 (7%)||11 (5%)||40 (17%)||48 (14%)|
Acceptable loss: Survey respondents were asked reason for loss. Fifty (16%) indicated zero (no loss). Forty one percent of individuals indicated 15% or less. 20% was medium choice. Thirteen percent said 50% of greater was an acceptable loss level. See table below.
Why colonies die?
There is no easy way to verify reason(s) for colony loss. Colonies in the same apiary may die for different 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 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 chronic paralysis virus. 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 effects 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 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 our and their environment. 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.
Winter Bee Losses of Washington Backyard Beekeepers for 2020-2021
by Dewey M. Caron and Jenai Fitzpatrick