Tag Archives: colony loss

Comparison of PNW and BeeInformed Surveys

One objective in starting a record of PNW losses was to “ground truce” the BeeInformed loss surveys. Both BIP and PNW surveys include the same general population of beekeepers (mainly commercial for colony numbers and hobbyists for individual numbers) and annual average loss percentages are computed the same way.

In 1/2 of the states/years the numbers are in close agreement (under 5% difference) but curiously the most recent survey year results exhibits a considerable difference in average loss levels (8.5% or above).  The BeeInformed average loss results for 2017-18 winter losses are 8 plus percentage points higher (for Washington) or lower (for Oregon and Idaho) than the PNW survey results.  The table on next page includes the summary numbers of % loss, number beekeeper respondents, number colonies they maintained in the fall of the year and, in red, the difference in winter loss average between the two surveys.

For the most recent BIP survey, 122 survey-returning OR beekeepers, with 19,232 colonies had an average loss of 24.8%. In the PNW survey, 319 OR beekeepers, managing 45,524 colonies had an average 15.9% overwinter loss.  The loss difference is  8.6%. The BIP survey with a smaller number of beekeeper respondents and colonies managed reported higher estimated loss. In  Idaho, the  difference  was a 8.9% reported loss difference. BIP survey of 34 individuals (managing 11,099 colonies) reported a 25.9% loss while PNW survey, of 21 individuals managing 52,010 colonies had a loss of 17%. As in Oregon, the PNW survey reported the lower loss level.

BeeInformed and PNW survey results also differed by the same approximate margin for Washington beekeepers this past survey season but the PNW survey reported the heaviest loss rate.  BIP winter loss rate was 21.4% (139 beekeepers managing 52,531 colonies)  while PNW survey average loss rate was 28.4%; it included 24 fewer beekeepers managing 25,959 fewer colonies.

The lower reported losses in Oregon and Idaho might be due perhaps to the PNW sample including a higher proportion of commercial/semi-commercial beekeepers with fewer in Commercials represented in Washington PNW returns. Commercial beekeepers in all 3 states typically have lower loses, by 50% or more, compared to smaller-scale beekeepers. In Oregon and Idaho the colony numbers of respondents are greater while the reverse is true for Washington individuals and this too could have impacted the loss percentages.

In three previous survey years, a large differential in average overwinter losses of the two surveys also was reported when there was a big difference in number of individuals or/or number of colonies managed by survey respondents. For example in the previous year (2015-16) survey) in Oregon, the BIP survey reported 5.6% lower loss level (the BIP respondent pool was 133 fewer individuals and 5855 fewer colonies). For Washington, there was a 9.7% difference in the two surveys in 2015-16 when the BIP survey, although  including 73 more beekeepers, had 4944 fewer colonies. In the same year, Idaho loss differential of 6.8%; The BIP survey included 34 more beekeepers managing  3,942 more colonies.

Why the most recent survey year differences are so different is not known. Generally the loss level numbers reported by the two surveys do “track” and if sample sizes are considered can be explained when the differences are over 5 percentage points.

Dewey M. Caron 7/9/18


2O18 overwinter Losses of backyard beekeeper with 10+ colonies

by Dewey M. Caron

The OR and WA beekeeper small scale beekeeper survey respondents www.pnwhoneybeesurvey.com are mostly 1-4 colony holders but there are several that have 10 or more, up to 50 maximum, colonies. One question I get is what about the losses of these small scale beekeepers who have  “larger” colony numbers – do they have higher losses? The short answer is NO.

For WA backyard beekeepers, 40.5% had 1 or 2 fall colonies and 26% had 3 or 4. The Medium number was 3 colonies, simple average of total 104 WA beekeepers was 4 colonies/individual. In Oregon of backyard beekeepers, 61% had 1 to 4 fall colonies. Medium number was 3 colonies and simple average of 303 Oregon OR beekeepers was 4 colonies/individual.

For the 2 PNW states, survey responses from 12 commercials (simple average 5826 colonies/individual), 11 individual semi-commercial beekeepers (average 128 col/individual) and 407 small scale beekeepers (simple average 4 colonies/individual) were respectively 19%, 28% and 40% overwinter losses.

For the 400+ OR/WA small scale beekeepers, 33 individuals (8%) had 10 or more colonies (24 OR and 9 WA beekeepers). Their range of losses was 0 to 85%. Medium and average loss was 20%. Of these 33 beekeepers, 7 OR and 1 WA (2% of total number of small scale beekeeper respondents in the two states) had losses above the overall loss rate (for Oregon that was 38% and Washington 44% average overwinter loss.)  Individual losses of these 7 individuals ranged from 57% to 85% of fall colonies. Medium and average loss was 67% for these 8 individuals

Looking at years experience, the range of individuals managing 10 or more colonies was 1 to 40 years experience; 15 (almost 50%) have 10 or more years of beekeeping experience. For the 104 Washington backyard individuals 65% had 1 to 4 years experience and for Oregon’s 303 small scale beekeepers, 56% had 1 to 4 years experience

Table on next page shows number of individuals by fall colony size (10+ colonies), their loss percentage and their number of years of beekeeping experience. Losses in red are the 8 individuals with heaviest losses.

It is clear that smaller scale beekeepers with 10+ colonies (up to 50) did NOT have higher losses compared to majority of the backyard beekeeper respondents in the two states.

Dead Colony Forensics by Dewey M. Caron

About a dozen brave individuals gathered at the Zenger apiary colonies Sunday April 15th, during a steady Oregon liquid “sunshine” rain for dead colony forensics with Dewey.  Photo right by Mandy Shaw.

Temperature was low 50’s, with only a couple foraging bees venturing forth from 4 of 8 colonies. We hefted boxes and did autopsy on two dead-outs.

Bees die overwinter for a number of reasons. By doing a dead colony autopsy we seek to determine what might have been the likely reason for non-survivorship.  Understanding the why might help us avoid a repeat this next winter.

The first dead-out we looked at (photo above) proved to be a tough diagnosis.

The colony was a mid-May nuc donation from Beetanical apiaries of Lane Co. Hive had a standard and a shallow. The shallow frames were quite full (>3/4ths of cells) with capped honey. The shallow was lifted off and placed on upside-down cover.  There were dead brood remains on three frames of the lower standard box plus a small (<2000) number of dead adult bees on the screen bottom board and outside the entrance. Two adjacent frames had widely scattered capped brood cells extending in an oval  covering over  1/3 of the middle of the frames; there was a fist-sized patch of compact capped brood but it was not contiguous with the scattered brood of the other two frames. There was no evidence of a dead cluster but a considerable number of cells of stored pollen on 5 frames. Ample mold was evident in pollen cells and as a powdery grayish mold on surface of cells. Colony was sampled for mites with a sugar roll in September and had only 2 mites (<1%).  It was NOT treated for mites as it was a non-treatment control. Colony was alive in a mid-October inspection.

Photo of the three frames with brood shows the frame with a patch of compact brood (held  in my right hand) and two frames with very scattered brood (one in my left hand and the third on top of adjacent hive; this frame is shown isolated in photo right). Full super on ground.   Photos by Deb Caron.

So what can we diagnose? Lots of honey and pollen stores so we can likely rules out starvation. Small number of dead bee bodies suggests a small colony but if we would believe death from a too-small population of adults, there should have been evidence of a cluster with bees within cells and dead bee remains on the frame(s).  There wasn’t.

Thus our best guess is a colony that had a BEE PMS condition. The scattered brood remains on both sides of the two frames suggests this –a spotty (snot) brood situation MIGHT have been diagnosed in the October examination, but this requires a close examination of the brood; we might have noticed evidence to too few adult bees to cover the brood – both are subtle clues. The fist-sized brood area,  one frame over from the other two frames with scattered brood, might have been bees trying to escape the high mite numbers and their unhealthy brood of the 2 frames with scattered cells. Adult bees were likely dying prematurely and abandoning their (unhealthy) hive, thus the reason we saw only a smallish number of adult dead bees. The colony likely failed to rear sufficient fat, fall bees. The colony probably died within a month after the last October inspection, probably from a virus epidemic related to the mite infestation. NOTE: The September mite sample is misleading/confusing (we would expect it to have been higher); if an additional sample was taken it would perhaps have been higher?

The second dead-out was a more standard necropsy. Hive was a spring split,that struggled all season. It had 2 shallows. Colony had a 19 mite count (6%+) in September and was treated with 2 formic pads between the two boxes. It was alive in March (this spring) but noted as small. It was fed dry sugar on paper (some still remaining) and provided with a frame of sugar candy.

Opening the top and removing moisture trap, (all Zenger hives had moisture quilt traps at top) showed a dead cluster of adult bees on 3 frames in top box at top of the box extending down about ½ way on the 3 frames (see photos; in photo right, hive tool is showing the remaining dry sugar on paper – quilt trap with wood shaving lower right). The adult bees were black and showed excessive moisture; there were many maggots (scavenger fly) feeding on the dead bees. There was capped brood in compact pattern within the cluster. Dead adult population was small (perhaps 8-10,000 bees). There was NO capped honey in any of the frames of either box. Lower box was empty. There were some dead bees on solid bottom board. There was little mold.

So what was diagnosis? The dead cluster is characteristic of a colony that overwintered the tough months (Dec-Feb) and moisture of adult bees, maggots and little mold suggests recent death. The compact brood shows the colony was starting to expand in the spring (flight was noted in March). Although dry sugar (as candy and crystal sugar) was given as emergency feed (hefting would have revealed lack of enough stores), it turned out to not be enough — colony likely starved. Bee cluster too small to generate enough heat to make slurry out of dry sugar or candy so bees couldn’t use it. Photo below shows one of three frames. We see “bee butts” under the dead cluster and compact capped brood.  Photo by Deb Caron.

All frames, except one with high number of drone cells, could be reused for anew colony installation (package, swarm, split). Brush off dead cluster and from bottom board. If inclined wash mold with bleach or vinegar solution.

Hive loss results

Send results and analysis about why I lost my hives

Response – We will send  although it will take a bit of time for analysis as we are something near 300 responses this season. Appreciate your and all others who did respond.

bee keeper challenges

It is very challenging to be a bee keeper, it is very expensive hobby. I am doing it to help the bees. It is very hard. You lose bees to yellow jackets, robbing …
Response –  You are certainly correct that when a colony dies that it is a significant loss of time and money. They are expensive. Trust you have better successes this season. Thanks for sharing

Survey mite assumptions & failed inventions

There is no selection in mite control for none as an answer it assumes all do mite control and I do not.
RESPONSE – We have a none for non-chemical treatment controls. Then a screen did you use a control – clicking none takes you past the specific controls to section 9 on queens. We do have another for all multiple answer choices and you can put none in there.

My bees are in a hard to feed area and I do well except in wintering. This year I moved them in to their bee house and failed to connect the entrance I invented with nosema and blocking the hive entrance. When I realized my mistake my hives were doomed to fail. Mostly my fault I should have 6 strong hives right now. I lost two hives in late September 15 airplane spray of some type then seven in January 16 I think five I killed with my invention 2 hard cold killed, I lost 2 in February march 16 hard cold snap week hive but one with brood and 3 frames of bees just died I think it should have made it.
Response – The main thing is to learn from the mistake – you had a good idea but it didn’t quite work out as intended. The losses you describe are too common for our area however so maybe it wasn’t just your management (or lack thereof) that was the issue. I trust this season will be different – at least the chance to make a different mistake with the bees.

Hands off experiment

This was great. Unfortunately, I may have lowered our percentages by being incredibly hands-off this year, as an experiment.

RESPONSE there is no one way to keep bees. No treatments, as an option rather than default, is one a large number of individuals elect. It does come with the cost of heavier colony losses. By seeking to capture different beekeeper approaches and their variations, I hope to have a widely representative survey. We do not have a good solution yet – some solutions lead to less overwinter losses while others are effective for one individual but not be for another. It is a difficult time for bee survival. Thanks for sharing.

At a loss on hive loss

I am uncertain why all of my bees died. Until I find out I will not keep bees this year.
Response – Even those individuals with more experience often cannot tell the reason for loss – and it is not necessarily the same for all colonies or beekeepers. We sometimes can eliminate one or more factors but then are still left with well it could be due to this or maybe to that, etc. Our bees are having a tough time of it – the reason for our survey is to document how many, probable why and what some individuals are seeking to do about reducing losses/improving success. We do not have the answers – it is discouraging to do what we consider the best and then to lose a colony or all of them. Trust you will seek to get back into bees at some point. Thanks for sharing.

Beekeeping Comparisons

I am curious about the differences in commercial beekeepers losses vs. hobbyists and urban vs. rural beekeeping losses. It seems that commercial beekeepers lose a lot. This year my very first loss was one hive, which I am proud of since I hear about veteran beekeepers of far many years experience whom loose half of their apiary to winter losses. I attribute my success to attending bee association meetings regularly and education through WA State Beekeeping program, reading sources such as books, internet and magazine subscriptions. Also the invaluable networking with other beekeepers and/or conferences.
RESPONSE – Our survey has found the opposite – commercial beekeepers have only about one-half the overwintering losses of backyard beekeepers – and this has been consistent in the PNW surveys now for a number of years. They lose heavier during the season than the backyarder beekeepers – they are requiring/expecting more from their bees and “using” them multiple times a year (for pollination primarily but also for honey production – they need more productivity to cover their time and costs.) What is “unique” about our current losses is that an individual may do the same management; same location, etc but have heavy losses one year and lighter another. Much we still don’t understand about bees – the survey effort is designed to enable you to look over your beekeeper neighbor’s fence. Networking and well-designed training materials and programs such as OR and WA Master Beekeeper programs are helping but are no substitute for the actual doing – to learn and benefit form understanding what bees are doing. I appreciate your sharing

Weak Swarm Hives

Most significant loss was 3 weak swarm hives to yellow jackets in September – should have requeened. Thanks for conducting the survey!
RESPONSE – Weaker colonies are always more vulnerable. And what a great yellow jacket year it was (for them) – hopefully they will have smaller populations and fewer successful nests this coming fall.